How neat will a job like this done with tin-snips be? And how tired will
my
hands get. I need to weigh that against the cost of gettings somebody to
do
it for me. Its only going to be a piece about 60cm wide (24 inches), but
about 20 cm high (8 inches) with rounded corners. Something like this :

http://www.chowns.net/cab/panelshape.jpg

The rounded corners will take some filing - what radius?

Not particularly big. I just need it so you don't catch you sleeves on a
sharp corner. Its going on a control panel of an arcade machine cabinet.

Like this (where the red dotted line is):

http://www.chowns.net/cab/panelposition.jpg

Sanded smooth and bolted down to another piece of metal, and then
painted.
This is steel, you don't sand it smooth, it comes smooth.

I meant sanding it where I had cut it (I am assuming it won't be super
smooth on the edges)

Oh yes, and you didn't answer my tinsnips question. (Thanks for all the
advice so far though!)

Regards
Stephen