I know it isn't open source... and maybe not even possible at all... But it would be awesome if there were a way to stick Photoshop 7 on a USB key drive, or whatever to use on any computer you want to use it on.
I hate having to connect to my computer remotely (using Remote Desktop Connection) to use Photoshop 7, and then have it be all laggy and crap.
But once again, I don't think there is a way to do this because of registry keys, etc. Just a suggestion though. Or rather, something to look into.