I sold a '77 Mugen kitted CR125 to a forum menber not so long ago, and there was a '76 CR125 on ebay (US) last week, complete running standard bike with mugen kit, Simons forks, swingarm, NOS sun rims and a pile of stuff for US$5,200. Was tempted but already have enough to do. It didn't get a bid, so may be re-listed some time.
Cheers,
K