I am the author of UltraClipboard, and I have made a portable version, and I am wondering if you think it will be helpful at all in your "PortableApps.com" site.
It is not an opensource project, and only runs on windows, but on all versions.
If not, thats fine too.
I haven't published the portable version anywhere, but the regular versions can be found at: UltraClipboard.com.
Thanks!