They really ought to do something like that as I doubt that they'll make it to $3m and it's such a desirable thing to add. As long as they don't destroy the source code they should be able to create the kit at any time.
If that really seems like a legitimate idea, maybe someone should pop off an email mentioning it to Fargo. (Unless, in all likelihood, he's already considered that, which he probably has. :P)
EDIT: $51, 000 to go! Almost there!
(Again, for me at least; I quite want people to be able to get Avellone on board.)
The idea has already been posted to one of the most recent updates. It's much more likely to happen than other ideas just because the mod kit is largely separate from the game itself and can be completed at any time, provided they maintain the source code.
EDIT: The true figure may be higher because they're taking payments through their web site as well. I really hope they make it to $3m and can include that kit.