Well just some more opinions to stir things up some more.
-Clamps: The common worm clamps Honda used are also used on the majority of cages on the road. Installed correctly, they should not leak, period. I found a couple that weren't quite snug enough when I did my t-stat and cooling system service at the spring of 2011, snugged them, and now- over 55k miles later, over 80k on the bike, ridden in temps from 100+ to -19f, there has never been a leak. Volvo and Saab have used constant tension clamps for their turbo tubes, and they have to be replaced often because the springs break. I always replace them with quality worm clamps, and have never had to replace one again. I prefer to have one less possible component which could fail (the spring).
-T-Stats: I couldn't care less where they are made. Having worked as a GM & Chrysler tech at different times, I have seen those American brands with China, India, Korea, and Brazil on labels for factory replacement t-stats. Considering our very own Honda t-stats are the ones which were sticking (could have been the paint many suspect, or could have been the t-stat itself), I really don't think we should be praising Honda's t-stats over someone else's. Oh, and as for source...doubtful they were from an early beetle, as those were air cooled and had no t-stat. Possibly another VW from the 70s, when liquid cooled models first came out; or for the later New Beetle.
-Many parts interchange as cost-savings measures, even by OEMs. My Honda lawn tractor uses the same oil filter as many Honda cars.
I happened to use an OEM t-stat for the replacement only because it got here first (thanks to Blrfl) for a trip i was taking, otherwise I would have used the t-tom one I had ordered, and not lost sleep over it. I sold that one to another member, and haven't heard of any issues with it.
If you have leaks make sure the original clamps are tight enough; that the hoses aren't starting to dry and split/crack; and that the metal the hoses go over isn't corroded. Also make sure the hoses haven't softened up from age, which can lead to small leaks.