I would try DIY P2P or "Paranoia" as it is the name of the application... It's a demo p2p application... Fully functional and it will let you create your own privat Gnutella network,and you can also run it in forced ultrapeer...Her is the link:
Paranoia - Reviews and free Paranoia downloads at Download.com
If that link is not working,you can send me a PM and i can give it to you... Or you can try use Gnucleus her on the forum, since the DIY P2P is mostly based on Gnucleus source code... You find the installer her on the forum in GnucDNA section:
http://www.gnutellaforums.com/gnucle...installer.html
I hope this can help you some way....