"Are there any reliable recorded instances of a CHL holder needing or using more than 7 rounds, or needing to reload?"
I've mentioned this before, but it's probably worth repeating.
There aren't a lot of shooting cases involving CHLs because not many CHLs actually carry and there aren't that many CHLs in the first place.
In TX, CHL holders make up about 2.2% of the population. Based on an informal survey of members of a local gun club (people MORE likely to be carrying than the average CHL holder, in my opinion) less than half of them carry on a regular basis.
That means that at any given time in TX, it's reasonable to assume that about 1% of the population is carrying with a CHL.
Last year (2012), the incidence of violent crime in TX was 0.41%. Let's ignore that a lot of those crimes take place in the home (where having a CHL is a non-issue) and assume that all of them took place outside the home. That's going to inflate our numbers, but I think the point will still be obvious.
So the chance of a CHL holder who is carrying becoming the victim of a violent crime in TX in 2012 was about 0.0041% Put another way, out of every 24,390 violent crimes, one of them will be perpetrated against a CHL holder who is carrying. That amounts to less than 5 every year in TX.
From the statistics about self-defense gun uses, we know that about 90% of them are resolved without firing a shot. That means that on average, every 2 years, a CHL holder in TX will likely have to fire a shot in self-defense.
All of that to say that ANY incidents involving a CHL holder having to fire a shot will be VERY rare. Therefore, the fact that one particular brand of incident (one requiring a reload) is rare really doesn't tell us anything at all. ANY incident involving a CHL firing a shot will be very rare.