afecelis I don't even know what the MY3D format is! I wasn't the one that originally asked that question!
the MY3D file should have nothing to do with the drawPrimitive functions. The problem is in OpenGL, even if you use the proper fix ( which I believe Niko put into 0.8 ), OpenGL has a hardcoded limit for the number of vertices.
For instance, my DX CAPS tells me I have a MaxPrimitiveCount of 1,048,575 and a Max Vertex Index of 16,777,215. There is no way that I know of in OpenGL to determine this max, so it's hard coded as 65536 ( which is WAY TOO LOW ). That hard coding is in CVideoNull.cpp in the function - getMaximalPrimitiveCount.