To answer all the questions:
I felt around inside the tire; nothing. I just pulled the tire off in the comfort of my house and the tire's perfect. No puncure, no debris.
The puctures occurred in different places in the tube, but each time on the inside, facing the rim. I just checked my last patch and it's right over a spoke hole.
I had another flat after I put the Velox tape on, though I think it was because the tape was pushed to the side. Stupidly I bought the 1cm Velox as opposed to the 17mm. I had the original rim tape wrapped around the Velox, but they look like they were both pushed to the side. When I got my next flat (number 7), I put the second roll of Velox on the same rim, so I had 3 layers of tape--2 Velox and the original tape (which was the more elastic rubbery stuff). That's also when I decreased the tire pressure. After that, no flats.
I'm pretty confident that inflating the tire to a high pressure contributed to this problem, since I flatted much more quickly when the tires were fully inflated, and once I dropped the pressure down way low I had no more flats.
I also checked for burrs, and nothing significant, though I suppose there is a VERY slight burr around some of the holes. How should I smooth those out?
Looking at the wheel again it does seem like it would be very odd for the spoke to be causing this problem. They are far from the tire.
I don't think they were pinch flats since I've had those before and none of them had the tell-tale "snake bite" holes. They were all single hole flats. Plus, I had 7 of them, and there's n way I'd have 7 pinch flats in 60 or so miles.
It was not happening inthe same place each time, which also puzzled me.
This is pretty wierd. The most logical explanation is the holes in the rim were causing the problem, but I've never had this happen before.