The installer for Vicidial is called "Vicibox". It is available at Vicibox.com
At present it installs the Developer version of Vicidial which is 2.8 and is considered stable. Vicidial's model has been stable (and in production!) in the Developer's trunk since some time around 2.4.
However, 2.7RC1 was the last "release", but is not getting bug fixes (and probably not even security fixes) because 2.8 is stable.
Since Vicibox ALSO installs Asterisk, there is no need to really discuss it. However, Vicidial is compatible with asterisk 1.2, 1.4 and 1.8. But it is a patched version of asterisk that is installed with the installer (of course you can download and install the patched version yourself if you love doing that sort of thing(, but really the Vicibox installer has made it possible for 98% of users to just .iso and go.
Vicidial WAS originally on Slackware, and I've personally only bumped into one company using it on that platform today. Debian has had a few discussions, but we've only had a few clients on it and many of those have migrated to OpenSuSE during an upgrade eventually.
Vicidial WAS also on Ubuntu for a short time (one version, which we liked quite a bit) and it was quite popular. In fact, I think that is still the only version that has a Live Demo CD. PoundTeam is still trying to find time to complete our Ubuntu version of the latest installation of Vicidial (clean, stock install!) so that those who liked Ubuntu can go back if they desire. Kumba maintains the official (OpenSuSE) installation iso, and we're not looking to replace that, but we have a lot of respect for Ubuntu and want to offer it as an option again, since The Vicidial Group has no intention of bringing it back.
We actually have had several running prototypes, but have never had time to publish before an upgrade was necessary ... and then clients make us too busy to finish and it gets delayed. LOL Presently we're back waiting for a chance to finish migration to MariaDB to stay "in line" with the standard Vicidial stock systems.
Advice: Just download the .iso from OpenSuSE and install it in a Virtual server today. Work out the rest after you've had a functional machine (virtual is only good for a single agent, but that is perfect for "auditing the course"!). Then you can debate the wisdom of inventing your own installer. Or if you're interested in helping us out with our Alpha of Ubuntu Vicidial, give us a call.
(Note I did not offer you a free server! Don't even try that! LOL)