boltman,
Those models I listed were not from any websites, they came off the pages of current wholesale catalogs. As a gun dealer you merely have to order the gun from the manufacturer. If you are a small dealer doing a small quantity business (like I used to) it is much easier to locate it from any number of wholesalers......... like Jerry's Sports Center for example.
The 6.5 x 55 is much more available than most folks believe. It may not be as easy to obtain a large variety of different guns in this cartridge chambering compared to the .260 (at this time) but if somebody wants a 6.5 x 55 in a modern weapon he could have it in a matter of 4-7 shipping days. All it takes is a dealer (like yourself) to pick up the phone and place the order.
There is not a lot of knowledge out there concerning this cartridge and the loadings and chamberings currently offered. You can find just as much 6.5 x 55 factory ammunition as the .260 (at this time). And it is sometimes cheaper than the .260 but never more expensive. More ammo companies currently load the 6.5 x 55 in more of their lines than the .260, but in time this may change. I'm not diss-ing the .260, on the contrary it is a wonderful round that has captured the essence of the benefits of the .260 bore in a modern available case. It should be a smash hit. Time will tell.