Jtek is working on an adapter for nexus 8 speed hubs so you can use barend shifters. Combine those with some Paul Thumbies and you would be close. Or mount the barends on the downtube.

Friction shifters will not work with modern, more than 3 speed hubs.

http://jtekengineering.com/index.html

Edit: add link

http://www.bikeforums.net/showthread.php?t=392104