Just saw today that Amazon is branding their own SDHC cards. Class 6 and Class 10. Pretty good prices on them.

Anyone have any idea who's manufacturing these or how reliable, (if at all,) they are in the HM700?

Call me old-fashioned but I'm a firm believer in sticking to name brand products, especially ones the manufacturer has recommended.
I've wasted a lot of money over the years buying all sorts of products simply because of the price.
In the long run, I would've saved a lot of money by spending a bit more initially.

I'm right there with you. Every card I've put in my camera is a Panasonic, and I've had zero problems, (save for one instance that forced me to format a card with footage on it. I'd already pulled the footage off the card, and it was strictly a "pilot error" situation. Card is fine.)

Just was curious if anyone had used these, or had any idea who the manufacturer was on these.

I haven't seen or tried the Amazon branded cards, but for the past year I've been using Transcend 16 & 32 GB cards, both class 6 and 10 (haven't really seen much difference in the 10's) that I've been buying from Amazon and I've never had any problems with them. I once tried a MicroCenter 32 GB branded cards and had problems with both of them.