There is a vintage Mark Nobilette 25" lugged steel frame for sale in Brighton, MI that is currently listed on Craigslist w/asking price of $690. Frame appears to be in mint condition from pics posted in ad:
http://annarbor.craigslist.org/
This frame was built when Mark worked out of the Cycle Cellar store in Ann Arbor, prior to his move to Colorado. Brighton, MI is about 25 miles north of Ann Arbor, as a reference.
Dave Patrick
Chelsea, MI