I've built lots of stands, and I looked at the glass cages stands (when I picked up my tank from them). I like thier stands but the design that glass cages uses is very simple, and assuming that he already has the right tools already, the materials to build the stand and canopy will only cost about $200 - $250. It's a simple design, so he can probably build it in one or two days, and it's certainly strong enough to hold your 75 gallon tank with no worries about breaking the tank. Just let him look at the pictures of the stands, and ask glasscages what thickness plywood they use on the 48x18 stand? (3/4" or 1"). It would save you $300 - $400, and you'd have the stand sooner, but there's another reason that I think you should reconsider letting your husband build the stand:
In general, one of the differences between men and women is that a man's identity and sense of value is more stongely tied to his ability to competently provide for a wife. For most of the last 300,000 years, a big part of that competence was his ability to make things (houses, tools, fish tank stands). That's why we want to do that kind of thing, and want to be appreciated for it by our wives. Most women aren't wired that way, but it might help you empathize to imagine how you would feel if your husband said "I really want us to hire a full time nanny to raise the kids, because I'm afraid that you won't do a good enough job." (ouch) He could build two or three stands for the price of the glass cages one, so if his stand isn't nice enough, sell it on craigslist and let him try again (building projects are always better the 2nd time). If he's truely bad at such things, and there are safety issues, then for get it and buy one, but otherwise I would urge you to let him show his wife what a good provider (builder) he is.