Most of the giant millipedes available are still wild caught I believe. Does anyone here keep and breed successfully any of the large species?
I've bred a number of species of millipedes over the last 15 or so years and the one thing I've found all of them to have in common is that they seem to do much better the less disturbance you put them through; I used to keep a few species in under-bed storage boxes (~3ft x 2ft x 1ft) and I just filled it with rotting leaf litter and white wood and let them get on with it, with some additional foodstuff. Six months after they went in there was usually a good slack handful of young which developed well, although only if I left them well alone!
The majority, as Mr. Zootycoon states, are still WC but I think that this isn't simply down to the difficulty of rearing them (with some species it is however), but more that it's much easier and cheaper to import animals that can be sold/displayed almost straight away, rather than investing a lot of time and effort into rearing a population; I'd rather do the latter personally.. Maybe I'm just jaded about the pet trade though...