Can we render the programmed mob somewhere within the factory structure.
eg. TileEntityMobSpawnerRenderer/renderMob

This would be neat. I could just picture the main mob containing block looking a bit like an encased vanilla mod spawner like this :)

Yeah this is great, as then you can see in one glance which mob is currently being killed.

Maybe have it able to be set to on or off in the config to aid in those who want to keep lag down on a server

Chances of my adding this are pretty low. I think it was a good idea at the time, but to be honest, I had writing rendering code. So this is way down low on the priority list, but if ever implemented would definitely have a config option.