'Fraid not!
You'll need a tower if you want a graphics card, as you'll either have a Mediator PC bus or a Blizzard PPC thingy which runs very hot.
I got my Power Tower from
www.amibench.org for a very reasonable £35. It's made of metal and is very sturdy and will give you plenty of room for expansion.
If you go for a Mediator you can fit a 3DFX Voodoo 3/4/5 PCI card which is pretty much all you'd need these days.
