This is a new one for me. I don't ordinarily do testing, unless I suspect I've got a problem, but out of curiosity, I decided to try Sam's test with K10. I had interesting results. I tested a FA35 f2.0, FA50 f1.4, FA77 lmt, and a FA135 f2.8. Just for kicks I added the FA28-105 f3.2-f4.5 @ 50mm to the Mix.
This of course is not the most accurate test, it is just to get a general idea. It seems I have a little front focusing, at minimum focus distance with both the 35 and the 50. It's not to bad though. If I backed off some, the situation improved. Both the 77 and the 135 were dead on. Oh, and I got the shock of my life when I pixel peeped at the 135, wide open. I always new this is a very good lens, but this thing is not just tack sharp, it's razor sharp. I'm going to have to use this lens more often.
My off the cuff conclusion is the body is fine, and I probably have had the same FF issues with the 35 and 50 on my DS all along, but never noticed, because I'm usually stopped down a stop or 2, and DOF is covering it.
Sam, I'm glad you were able to resolve your issues. You obviouly had one that was out of calibration. Now go out and have fun with it.
Cheers
-Alan