Hey Ian,
I'd like to get your attention on this issue and give you some food for thought. I'm a Linux based professional. I am willing to pay 2x the MS version price for a Linux based version of UE.
For that price (per user or seat), I would want to be able to deploy it into my site via auto/jump/kickstart on all the machines I administer and develop upon.
I firmly believe the maturity of the Linux market is sufficient for your business model to seriously consider a platform agnostic release that would blow wide open your potential market appeal.
Certain questions come to mind when pondering a Linux release:
1. Should you provide a terminal (curses, s-lang, etc) based version that doesn't require a windowing environment...ala Joe, JED, and VIM?
2. Will you want to integrate in with existing development tools?
3. What are the key elements in the MS version that have the Linux community drooling?
4. Should you attempt a port or ramp up a UE clone?
5. Is it possible to leverage existing OSS and significantly fork off a project with your own key code?
6. Are you willing to release source if you enter the Linux market?
7. Can you deterministically release a Linux version with the same eye for exceptional quality and support that you have built for MS UE?
So far this has focused on UE...but I believe UC has equal potential.
Naturally, there are dinosaur purists out there that will thumb their nose and stand firm on the vi/ed-diff-find-sed/awk cocktail of legendary, borg-like, command line cryptography while ironically waving a flag of "live free or die" and stunning economists with outrageous salary demands; however, with all due respect to our UNIX roots, the dinosaurs did, in fact, become extinct.
I am certain there are dozens more questions that will (and should) factor into the equation. I have my opinions on the answers to the above questions; however, it is your answers that would provide the direction, tone and tempo of any such adventure.
There is clear evidence of interest. I would like to see more depth and detail in this discussion. Perhaps the discussion will provide you with enough passion and business incentive to address this burning desire.
Richard Wermske
Technical Architect - Veteran of the Psychic Wars
Paragon of Principle-Centered Pernicious Pleadings
http://starbase.airweb.net