If you cut off their hind legs, they will not be able to jump... but chameleons do still eat walking locusts...
If the hind legs seem particularly strong/hard, and have sharp serrated edges, it might be best to cut the legs off - especially with a young cham.
A healthy cham should be able to deal with a whole locust of the appropriate size (they do in the wild), but even so, there is no need to risk potential cuts to the mouth, that could lead to infections and vet bills.
I'm not sure how big a 'small or medium' locust is. They don't sell them over here, and the ones I've caught in the wild vary in size depending on the species of locust.
But just apply the general rule: don't feed crickets/locusts/roaches that are longer than the width between the chameleons eyes (which is the same as saying the bugs should be just a little smaller than the width of the chameleon's jaw).
Firstly, the pet reptile industry is still growing here, so the feeder insect business is not as well established. Mealworms, superworms and crickets are the only feeder insects that are easy to come by. But the variety is increasing. There is one supplier that is distributing pheonix worms at most of the pet stores/reptile expos nowadays, and there is a seasonal supply of silkworms.
Secondly, locusts are generally considered a pest species here, and have in the past wreaked havoc on our agricultural industry which is quite focussed on grain crops like maize. So I don't think there would be anyone in the agricultural industry promoting the large scale breeding of locusts.