I've had a 40B for about a year, which is my first reef tank. Good footprint, easy to moderate flow, lots of surface area for smaller fish, easy/relatively inexpensive to light, and the width/depth make it look much larger than it is. I'm a pretty short guy, so although the 65 has the same dimensional footprint and would be nice to have, the extra height would be tough to work with. Mine's not drilled so it looks like a mad scientist's lab (large HOB skimmer, converted aquaclear baby 'fuge, canister filter, etc.). That said, the 36" length does limit the livestock options and i'm about to upgrade to a shallow 66 long for convenience, but I will continue to enjoy the 40B and use it as a secondary nano reef. Can't really go wrong, with the 40B, and they're pretty much always in demand if you decide to sell it and upgrade at some point. That Mr. Aqua tank really is a steal, though, and I'm surprised nobody's claimed it.
As for stands, there are a number of builds on this forum, but I've built and used a version of a King of DIY stand from a youtube video he put out two years ago titled "How to: Build an aquarium stand/canopy." I'd link it, but I'm not sure how to on this forum. Really straightforward directions and the thing was basically an inexpensive wooden tank that could be modified to your creative heart's desire. Add a few coats of plastidip and you have a presentable stand with plenty of room to drop a 20L sump/refugium under.