You can get reloading die sets for them. Component bullets a available but maybe not now (??) with the hoarding that is going on because of OBAMA's election and the legislation being considered after the shootings.
At one point someone was making a 9mm barrel for the CZ52. The 7.62 x 45 ammo in Europe is loaded at or hotter than 9mm so using a 9mm barrel probably would not hurt the CZ52 frame or slide.
I have a CZ52 and it is indeed a unique gun. I reload my own and it does a pretty good job of making a fireball with each shot (my loads are no more than the reloading manual recommended loads). It is a very well made, robust gun.
I think the surplus 7.62x45 dried up quite a few years back. Last time I seen it regularly in the importer's catalogs was in the mid/late-90s when the VZ52s were still dirt cheap on the market. They're still pretty cheap but no cheap surplus 7.62x45 ammo anymore.
I remember seeing conversion kits (chamber sleeves) back then to convert em to 7.62x39 and using a VZ52/57 magazine.
Actually, still available (ebay link), but I have no idea how well they actually work.
You could also refit a VZ52/57 barrel to a 52 if you can find one since that variant was a arsenal rework to 7.62x39 with a new barrel & mag.