Hi Will,
Up to this point I've tried really hard to be media agnostic (not dealing with any format specific issues). Once I decide to dive into dealing with various format issues I have to worry about all sorts of stuff I'd rather not deal with (patent issues, licensing, etc).
Splitting files would be an area where I'd have to do that (it would require decoding the file, splitting it, then re-encoding it), so unless some other reason forces me to go that route (like enhanced podcasting) it's unlikely it'll ever happen.
Let's just hope RIM sees the long file issue and fixes it from their end
-Marcus