OK, I'll address a few things here. First off, I am a certified Triumph tech, and have been with a Triumph dealer in the southern US for just under 3 years. I'll never claim to know it all, but if I don't know, I won't blow smoke up anybodies arse, and do my best to find out the answer. I have been wrenching on high end auto's since the early 70's growing up in a family owned shop in NY. I held an ASE master cert for 20 years, and a NY State inspectors license for 25. I started working on bikes as a kid. I'm also BMW, and soon to be Ducati certified. In short, i've been elbow deep in engines for most of my life. I have a clue
As for the engine rattle. It's a problem on mostly earlier bikes, and while the engine can sound like a diesel, the odds of it causing an engine failure is low. I've only had two instances of it so far. The problem is how the gears were machined, causing a poor mating between the crank, key and gear. Why Triumph hasn't gone across the boards with an SB on it. Not enough failures, and not seen as a safety issue would be my educated guess. We've sold about 25 R3's, and also service other sold elsewhere, and only having two with the noise is a pretty low ratio. Hell, they haven't done a thing about the broken spoke issue that has been ongoing on the Bonnie's, and when a spoke goes through a tire at speed, were talkin a real safety issue. As flip implied, I'm not in the front office, so there's only so much info I can get my hands on.
As for my comments on the 10K valve check / adjustment. The dealers do it at 10K because that's what Triumph recomends. The engine has had ample time to break in, and valves seated well. The early mileage on the engine is the time when the most ware is done, so I completely understand why they want them checked at 10K. They also said dureing training, that more then likely, if you adjust at 10K, you'll more then likely not have to touch them again for almost the life of the bike. As a tech when you check something, and more often then not it doesn't need servicing, you tend to form the opinion that it's wasted time. Time is money folks. This isn't at home with a brew by your side, Grateful Dead blaring from the boom box, and playin with the bike on a sunday afternoon. Doing valve adjustment on a R3 is a pain in the arse, and you can make more money doing other jobs. This is pretty big to a guy who's working flat rate.
People have been marking stuff on their cars and bikes since I was a little cuss to assure the tech does the job.

Who's to say that the tech can't just clean your markings off. How do you know he did it or not. I still do the check at 10K, but the techs I've spoken to that have since stopped doing it, do not charge for it, and the service price is adjusted acordingly. The way we do it with the BMW's is listen to the bike, and ride it prior to the actual service. If it sounds like the valves are loose, or it's not running well, we check the valves. Their latest engines don't even need them checked till 18K. The meterial the parts are being made of has much to do with this. In the future, you'll see bikes going 50K before you have to touch the valves.
As for doing a compression check to us as a guage for checking the valve adjustment. It's a BS method to be honest. Valve lash needs to be checked the old fassion way. Again, the meterials used in the valve train are far tougher then in years past, so they tend to stay in spec.
Something I'd like to make a note of I've learned about internet forums. We tend to only look at our own little world, and don't look at the bik picture. Howmany of a model is sold world wide, and how many have the problem. Quite often, what is actually a fairly isolated problem, looks like massive issue on a model spcific forum. There's also good info to be found often, and great people to discuss stuff with.
Cheers