I am doing a warm restart ("Restart" from the special menu in System 7). It will boot from a RAM disk-I tested it with a little trick. I created a RAM disk and fooled it into blessing it by using one of the System Enablers as "Finder". It blessed and booted, although, of course, returned a finder error bomb.
I didn't think, of course, that my fooling would actually work, but it did show that the mac booted happily :b&w: from a RAM disk. Only trouble is I can't make it big enough. Will check the links posted.
I'm not going to waste my time doing something without knowing if it's going to work. Something which will work 100%-fine, but not wasting money on something which doesn't actually help in the end.