Why not go for H.264?
You can easily get a mp4 file using MPEGStreamclip. I do this quite often.
I use this setting when exporting files for quick preview
Compressor H.264
Qualty at 50% to 65%
Frame Size 640X360
Better Downscaling Selected
One more thing, maybe the compressors that you are using have presets with mulipass setting on.Since you are not bothered about quality, you can avoid multipass compression.
Pradip Patil
Mumbai,India