I only plan for the S3D file format to support flat-shaded and (maybe gouraud-shaded) primitives. It is meant to be small and simple. For textured primitives, TMD or MD2 would be better alternatives. This 3D file format was designed for the PS1, and isn't ready for widespread use.
version 00 (prototype)
The limitation of this version is that it only supports POLY_F3s and POLY_F4s. It can store up to 65535 polygons and 65535 vertices in a single file.