Awesome! I've been curious about doing this too. I really like how RCT3's set were modular and were pretty much like lego pieces. Shy Guy's Main Street Sets being one of my favorites. I'll be happy to contribute to this idea of RCT3-like building. How large do your pieces span?
Kyle, If It's okay with you, could I post these files (I'd keep them updated as you released new content, of course) in the seeds/flatrides/3ds library thread? I'm sure other users would appreciate multiple ways to find your files. If you say yes, I could take care of everything, and of course, I'd mention that giving you credit is required by anybody who uses the files.
anyways, hope you can get back to me about this soon
-meta
Head Moderator Director, Structural Engineer - PEAK Amusements Site Contest Judge (Supporting) Chatroom Admin