U talkin full rifle or conversion kit? Gunbroker has a used 68 rifle on there now...Ive seen conversion kits on there also from time to time. I have a 6.8 and love it (actually got it on gun broker years ago).
Check with navalbeaver on here also...he may be able to get kits, not sure about complete rifles though. Kermit is good too...id try him again.
Actually, there is a nib 68 on gunbroker also.