Chimera tank plus sherman m4a4 mesh and texture would be amazing; replacing the lazer beams with shells, and replacing the sounds and such. just an idea. two mods linked below.
http://www.nexusmods.com/fallout3/mods/3981/?
http://www.nexusmods.com/newvegas/mods/47142/?tab=4&&navtag=http%3A%2F%2Fwww.nexusmods.com%2Fnewvegas%2Fajax%2Fcomments%2F%3Fmod_id%3D47142%26page%3D1%26sort%3DDESC%26pid%3D0%26thread_id%3D735234&pUp=1