This news is a bit old, but we missed it the first time around, so here goes.
Loren Petrich has said if there's interest, he will modify the MML (that's Marathon Markup Language) used in Aleph One (the open source version of the Marathon engine) to support models made by a program called DimAnimator.
The reason? Spnkrghol has been cooking up some great models for use in Aleph One.