SchokoKeks: its webgl, yes.
MasterQ32: someone showed me that yes, but that was after the ggj^^ and hey, ours is much prettier

I just spent the last few ours fixing my custom blender model exporter to handle bigger meshes, and putting together scripts to batch convert and resize textures to finally manage to convert the sponza model to work with my engine iSDGE on my iPhone 4S:

Its rendered at full resolution (960x640) and 4x multisample antialiasing, other than that it is currently just plain rendering of the model with its textures without anything fancy.
The only problem is, that exporting the whole thing took about 15mins, so there probably still is a lot of space for optimizations on my exporter .