Very interesting find.
I wonder if this kind of limitation may apply to other .2da files as well. In my own KotOR game, I do have 251 slots used. Not much space for anything else there, it seems...
DarthParametric, in light of this report from ndix UR I suppose you'll have to pull compatibility between "Diversified Jedi Captives on the Star Forge 1.0" and a bunch of other mods appending to placeables.2da, including K1R?