I'm working on implementing an SMD parser. Which means you'd still have to manually export from OpenBRF. I'm currently working on animations, the idea is that you can preview your fully geared character, but i really have no idea how hard that will be.
The current models were exported as SMD from OpenBRF, then imported to Blender, then exported in three.js model format again. This is pretty silly, though, because SMD is already a plaintext format that is well suited for javascript parsing.
And yeah, the data size is pretty big, currently 1-2 MB for each armor. The good thing is that browsers cache the stuff, so it won't be redownloaded again and again by the same user.