@sMe
I think you'll find it IS illegal to do what you're suggesting. Ever seen a sentence similar to this...
"This work may not be copied or distributed without the copyright holders permission..."
or something similar?
Using two copies of the same thing at the same time whilst only paying for one (unless this is covered by a license agreement) is illegal, period.
People get this confused with the common message that the big companies are less worried about the 'casual' copying you describe, and more worried about people making money. Basically - they know they can't stop casual copying as easily, so they concentrate on the bigger fish (i.e. commercial pirates, napster etc etc etc.).
Bottom line is... making and using a copy of a copyrighted work, at the same time as actively using the original is against the law.
So.... if you make a copy of your Kickstart ROM, and then JUST use the original, it is, in theory, legal. However, if you do use your original machine at the same time, then it's not legal.
The only way you could do this legally is if you buy a licensed copy of the ROIM image (a la Amiga Forever), or have a second old amiga kicking around in a cupboard not being used.
Man - this debate could go on forever.
Luckily I'm too knackered to carry on :-)