Metal router?

I'm trying to zealotishly convert a friend of mine to CNC - at the moment
her small business if paying a fortune to have stuff cut at the factory, who
tend to treat her small-demand jobs as really low priority.


Deciding "Hey! I can do this! I can help you!" I may be looking to build
something similar to a high-speed router for her.. But there is one little
problem: it's for thin sheet metal (~0.5mm), not wood.

But what can you use to reliably cut thin sheet metal at a high rate
CNCwise?
Pneumatic die grinder? A wood router with lots of cooling and TCT bits?

It needs to be a big machine, to take the stainless steel/ali sheets (4x3ft)
direct as they come from the factory. I was wondering if anyone has any pics
up of a machine of theirs that does this sort of thing already? All the
routers I've ever seen are wood-eaters only...

Any suggestions would be great
Thanks again for the help!
~Abby