There is a Fujinon TS 150/5.6 for sale on eBay: http://cgi.ebay.com/Fuji-G690-150mm-Fujinon-TS-1-5-6-6x9-rangefinder-Fujica_W0QQitemZ120241022913QQihZ002QQcategoryZ710QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Starting bid is $9.99, but it will get much more expensive, as the 150mm is scarce and highly sought after. It's the only lens besides the 100mm normal lens to have frames in the viewfinder, therefore it doesn't need an external finder.
Cheers!
Sebastien
Edit: there's also a Fujinon TS 180/5.6:
http://cgi.ebay.com/Fuji-Fujinon-180mm-f-5-6-for-Fujica-6x9-G690-complete_W0QQitemZ150233041018QQihZ005QQcategoryZ30075QQssPageNameZWDVWQQrdZ1QQcmdZViewItem