You can do this in DX (and I assume OGL) driver already.
If you have the DX7 SDK and/or mfctex utility ( or D3DMulTex and OGLMulTex) you can get the renderstage arguments to do single pass multi-texturing.
If you have the DX7 SDK and/or mfctex utility ( or D3DMulTex and OGLMulTex) you can get the renderstage arguments to do single pass multi-texturing.