How many EX500 motors do you want? I have a pile of them. Unfortunately the condition of each is unknown and several are former race engines that were not treated well. If you plan to do a basic tear-down and re-fresh, then I've got a few.
If you decide to go with the CL bike that musiclucho mentioned, I might throw in a few dollars for the front fairing/headlight assembly to off-set some of your purchase cost.
As a third option, I have a complete running EX500 that is titled with no back fees. I'd let it go for a little more than the bike on CL, but mine you can test ride and won't be any title issues.