This journal issue is dedicated to who appreciates this gallery (few people so far, I hope more forthcoming appreciators soon) to explain them that my planetary models are not only a mere speculation on what it's not been detected by astronomers so far, but they're based on somewhat real data and are really likely.

"How does he do?" Explanation

1 - I have got a downloadable program named Systemic Console which owns already current exoplanet host stars radial velocities set and predefined parameters which allows to seek additional planetary companions around the star or to challenge currently detected planet either to find different models for a previously known system.
Thanks to this one, I've been able to build peculiar models for well-known exoplanetary systems.

2 - The files in the console are essentially a text file which includes Julian date (JD or HJD), radial velocities (RV) and standard deviation (e or "σ", also known as error in measurement). These data are usually available in Exoplanet discovery papers and can be copied and pasted in such text files in order to get a ".vels" and ".sys" file which are respectively "JD, RV & e files".
Now, how can you apply this method to nearby stars which are known not to host giant planets in tight orbits neither jovians in intermediate orbits? How can you infer certain planets around Alpha Centauri, Tau Ceti, Sigma Draconis et cetera? Here's the trick!

3 - Assuming complete fits for Alpha Centauri were already available with Systemic console as expansion pack, recently I found some papers dated at 1987-1991 and 1997 (plus some more recent from 2002 and online available RV measurements), which showed radial velocities and julian date of...WELL-KNOWN STARS NEAR THE SUN!!!

Alike Tau Ceti, Sigma Draconis, 61 Cygni A & B, Eta Cassiopeiae A & B, Omicron² Eridani, Delta Pavonis, 82 Eridani, Beta Hydri, Gamma Leporis, Zeta Tucanae, HR 4523 A et much more!

"Not-so-brief" summary on nearby exoplanets survey

Most of current astrophysics studies and missions to detect extrasolar planet are focusing on several sets of stars in constellation fields. Monitored stars are usually similar to Sun, but hotter or cooler stars are not excluded from the survey. Some observatories focus on nearby stars, stars which are close to our Sun (from Alpha Centauri to Zeta Reticuli, spanning 40 light years away from Sun). Neighboring stars are the most interesting examples because they may be the primary target to seek Earth-like worlds to settle in the future. Current observations have been able to rule out hot jupiters (planets laying closer than Mercury, ranging between 0.03-0.3 AUs from the star) in tight stellar orbits as well as Jupiter-sized worlds within and beyond the snowline (within Earth and Jupiter's orbital zones). Maybe jovian planets could be located in further orbits, although a recent study claims the lack of planetary objects at very wide separations (beyond 20 AUs).
New instruments are currently able to detect variations due to massive rocky planets in tight orbits and even few Neptune sized worlds in intermediate orbits (see HD 69830 and Gliese 581's cases). Limits to detection of low mass planets around neighbor stars predict low mass jovian (either massive terrestrial) planets in tight orbits and middle-sized jovians in outer ones.


Here what I found with my work

Integrating old RV sets and some new data with Systemic console, I've been able to generate ".vels" and ".sys" files for neighbor stars and I got a set of Solar system's kins as predicted, although with peculiar (and expected by me) exceptions.
Here some samples:

- Alpha Centauri A & B: RV files and expansion pack were already available at "Systemic Backend - characterizing extrasolar planetary systems" (a wonderful site), as well as the downloadable console I used for this work.
As confirmed by a recent study, planets down to 2 Earth masses may have formed within 0.5-1.5 AUs from both stars (the system is binary). Indeed I found for both a 3-planets systems, each one a rocky planet around the size of the Earth and the innermost one close to Mars' size. Here the work's been easier. Next ones have been harder but satisfying at the end.

- Tau Ceti: a private communication affirms the possible presence of a couple of "hot Neptunes" in close orbits around Tau Ceti, between 0.13-0.3 AUs. Nevertheless the mass measurement is highly uncertain and these worlds could be only putative.
Tau Ceti has always been a tough nut to crack because it's a stable star, used as stellar standard for RV measurements.
I loved too much the "Hot Neptunes" model and it did not affect the presence of outer terrestrial planets. Generating a ".sys" file I've been able to change few settings and to find something interesting.
Initially the mass of the two innermost planets was close to that of the Earth and outer ones around 3 times its mass. Adding a couple of outer planets between 4 and 11 AUs (inferred to shield inner planets from cometary bombardment due to the outer and massive Kuiper Belt existing around Tau Ceti) the masses of the former grew up and those of the latter shrank.
So I got two "Hot Earths" instead of two "Hot Neptunes", with 4 and 6 times the mass of the Earth. Then an Earth-sized planet just inside the habitable zone (0.7 AUs, exobiologists' veins chill), a half-the-Earth-mass Martian world (1.2 AUs) and finally a Neptune sized world at 4 AUs and a Saturn-sized one at 11 AUs which may be the "shield".

- Sigma Draconis: I inferred a hot Earth and a Saturn sized world replacing Jupiter, plus three rocky planets. I got back the confirmation.

- Beta Hydri: a low mass hot jupiter has been ruled out but the possible perturbation of 4 Jupiter masses object at 7.6 AUs is likely. Never confirmed.
I found no hot jupiter as expected, but I confirmed the presence of a jupiter-sized world at 7.6 AUs, but with the same mass of Jupiter (one fourth of the expected and this may fit well with the non-detection). Then a set of terrestrial planets in intermediate orbits, plus one slightly habitable.

Conclusions

I'm currently updating newer revisions of nearby systems and DevWatchers shall be notified. I mean to repeat my Sci-Fi systems are nearly solid, very very likely.
Moreover some planets previously undetected have been found thanks to this method (for example GJ 674's "hot neptune").