While I'm one of the first guys to say 'KotOR III!!, yay!', it's a lot of hard work to do EVERYTHING by yourself or even a small team of modders.
Imagine: Development for KotOR I started 2000 with a trailer to present at E3 in 2001. So eventually it took them around 2.5 years to finish the project with a team of professional devs (release was delayed because of the desire to deliver top quality).
Now they already had the basic engine (Aurora Engine/Odyssey Engine, used in Neverwinter Nights) so they only needed to tweak the things they needed rather than to create a new engine (even though they rewrote the engine for KotOR, they got the basics to work with). So you'll have to add the amount of time for developing an engine.
My thoughts considering these things, are not very positive. In the end it'll take at least 2-3 years for a game development department like Bioware. Now imagine how long it'll take for several modders that develop mods for fun and joy. (Also considering most of them have a job or another occupation)
So in a nutshell: I don't think a project like that will last very long (like most of the TC Mods of KotOR that are planned) and if it will last, it'll be a very long time until you have a working game for the community to test.
(BTW: We already have some people working on a game like that (Link