Stream mesh buffer and textures (Free version)

Is there any way in unity (FREE) to stream a vertex buffer (example loading some models in background while player has no apparent freeze?)

I want to know if same is possibile with textures.

I'm not speaking of LoadLevelAsync (wich load an entire scene... )

Actually I load files in a separate thread etc. But when it comes to do "mesh = something" Unity freezes and not allows me to do a nice experience for the player. Shouldn't be nice if unity allowed that?.. I could turn to mesh and textures small enough so that freeze is not noticeable but that will overload GC and also increase drawcalls insanely.