Manda
Just saw the thread, and am sorry to hear of your loss post-facto. I did want to take the opportunity to provide some anecdotal experience, as all kinds of info has been thrown at you. My experience is based on raising thousands of chameleons, primarily panthers, but have worked with veileds also. Everything I tell you is "been there, done that .... in quantity".
Some of the info that you have received so far is good, and some of it seems to be out on a tangent. All appearances are that MBD was the causative agent. As with all MBD, you can back up and wonder about where you came up short, and that is an inexact determination as the animal has expired, and we are unable to make changes in husbandry to impact improvement in the animal in question.
From what I have read, I would make some suggestions. First off, I would put no faith in calcium delivery via gutloaded crickets. I would rely far more on dusting, using a calcium with D-3 for every dusting, and dusting as frequently as every other day. People can offer suggestions about how much is too much, but it is relative to your own set-up, and we can be pretty certain that what you did come up short, and could expect the same results next time if things are not changed. Crickets lose much of what is dusted on them, and if not eaten within 10-30 minutes, may lose it all. I have dusted crickets every other day with calcium with D-3 for chameleons in the bright sunshine with no adverse effects. Note that the D-3 concentrations in all commercial supplement products is exceedingly low, as the animals need very little. I have never seen a situation where I suspected D-3 toxicity using commercially dusted products on crickets.
As for the cage, the fall, etc. A healthy chameleon would have handled the fall with perhaps a bruise at best, and that's being overly wary. Your converted cage would not be a problem in that sense. If it had MBD, it was destined to suffer one way or the other. That would explain the fall. It would explain numerous bone fractures.
In the future, besides increasing the calcium dusting as noted, you will need to be more on the lookout for early stages of MBD. They can be observed, and the animal restored to health. Oh, start with buying a chameleon that is at least 5" total length. Once a week, hold it behind the head so as to agitate it, and when it opens its mouth in defense, take an appropriate sized finger, and let it bite you. A firm bite (you'll know, and you can survive it just fine) will also show complete rigidity of the jaw and all skull bones as it bites down. You need only be looking at the head, not closing your eyes and wincing (just kidding .... its not bad when they are smaller). The earliest stages of MBD will be seen this way. If there is any, you should see a folding in the head bones as it bites across the bridge of the skull, just in front of the eyes.
If and when MBD is observed, you know you need to increase calcium. The best way is to get a liquid calcium supplement. The cheapest good stuff, IMO, is via Ronnie Buck at
www.cricketfood.com, on his supplements page. To my knowledge, he is selling Cal-Glucon. One drop per day for about every 20 grams of animal. You can see a vet as well, but he or she will give you the same or similar product. If you suspect advanced MBD, a trip to the vet is recommended, as more drastic initial intervention may be needed.
You can pull an animal out of the early stages of MBD in 3-4 weeks. If caught early, it will never advance to bow-leggedness or permanent deformation. Good luck.