Well I did some quick research, and I was able to decompile, edit, and recompile the agrunt(alien grunt) model to make it replace the metropolice model, minus the jumping, etc. This means I will be able to make this mod of SMOD truer to HL:Source. Note that while I will be including the models, I will not be including their textures, thus they will be missing texture'd if you do not have HL:Source.
If you're wondering why it's red, that's because of SMOD's randomization system. I just so happened to spawn a metropolice that was a red(tougher) one, and of course I had replaced the combine soldier model with the alien grunt's.