I got myself some about a year ago, and couldn't be happier that I did! No problems with them baking evenly, they turn out beautifully. Don't know the brand on them, but they are aluminum, and I ordered through ebay after a lot of searching.
I have just recently starting to use mine more often, and had a few of the wilton sugar sheets I didn't need for anything, so I used thm in my Cricut and it cut the intricate designs beautifully. It's actually encouraged me to start using it more and I'm addicted to my Cricut again now.
Cat - I've been there too! I hate doing fondant cakes in July and August in our area...I get up as early as I can to cover cakes this time of year to try to help the situation as much as possible. It's not as humid up the hill here today as I've heard it is down in the valley. Good luck, hope it gets better for you.
I'm in California, order exclusively from GlobalSugarArt. They always ship very quickly, sometimes within an hour of my order, and the one time that I've called them on the phone they were super helpful. I give them two thumbs up!
I have one that I got several years ago at LegoLand in San Diego, haven't seen it around since. I have seen the silicon molds around online and at Lego Stores though, those might work well depending on your design.