I have also thought about putting a modern wheel...the drop outs are 126mm..I believe the new wheels are 130mm...It is a steal bike. I read on Sheldon Brown's site that you can at times just fit the wheel in with out even spreading the rear triangle...Am considering this option. I will take it apart this weekend and take some pics...I think you guys may be right that it could be a uniglide...

Has anyone tried just fitting the 130mm in to the 126mm space?