[EGreg]

Can copyright law actually allow PayPal or another company to sue people who try to post such "redesigns"?

I doubt it, but just wanted to make sure.

[toomuchtodo]

If Paypal wanted to be shitty about it, they could file a DMCA notice against the host or bring up trademark infringement.

Most companies wouldn't, as these sorts of redesigns are done in good faith. There's always that one company though.

[EGreg]

I wonder if it would hold up in court. It seems like this is fair use... but of course fair use is up to the courts...

[toomuchtodo]

Most of the time, it doesn't have to hold up in court.

http://www.chillingeffects.org/