I've had a HK USP Tactical .45 for several years, but have yet to suppress it. It has the threaded barrel, match trigger, and elevated sight to accomodate a can, plus the recoil system is designed to work reliably with a suppressor. It is a very accurate and soft shooting .45, and I will get a can for it at some point. Just too many toys, too little time and $$$.
I see them around at gun shops so they are available.