Well, a few things you need or should share that will help us, or at least me, in giving any ideas for you.
1. When you say, "kinda tricked out", what do you mean by that?
2. By "had owned a t-maxx", I take it you no longer have the t-maxx, or want something in addition to the t-maxx?
3. Are you looking for 2WD or 4WD ST?
4. Are you set on a ST?
As for bolting a 2.5 onto something other than a Traxxas rig, anything's possible, in my book. I doubt you'll find another model that is a direct bolt-on, but so long as you can find engine mounts and have the correct CB and flywheel for that particular model, I suppose it's possible. I'd wait for some other opinions as well, because I'm not 100% confident on that, but if .21RC10GT can put a Collari .30 into a RC10GT, there's probably a way to drop a 2.5 into most anything!