If you mean genuine moccasins, not slippers or boat shoe type things, then I think you'd need to speak with someone like Hamish
About Pictavia Leather and Hamish Lamley the Pictish leatherworker
www.pictavialeather.co.uk
or Sally in Wales.
(there's something odd about the link on the site I originally posted; this is her youtube channel, and was updated two days ago with a really good article on lime bast)
If you can get to any of the re-enactors markets though, you'd probably find good conversation and resources there for any of the shoemakers.
Making real moccasins needs firstly good materials and secondly skill and a lot of time. They won't be cheap.
Personally I think they're worth it, but I make my own (not even suggesting I make for anyone else, it's just too labour intensive on my sore joints) and I know just how much work it is to do them properly. Buying cheap, you'll get edges that rub, folds that aren't rounded, leather that dries like a brick when it's been wet, etc., all things that end up making them uncomfortable to wear.
There's a leatherworking forum that is full of really good advice, like this thread,
Hello again. Im ready to make another pair of moccasins. So far Ive been using chrome-tanned leather but Im thinking of trying some vegetable-tanned leather for pair number four. Theyll be unlined so I want to use thicker leather to prevent excessive stretching. Ill also be using the same piece o...
leatherworker.net
I think they're one of the things that are best made for yourself
though I'd happily, and probably will have to as I age and ache more, pay a decent craftsman to make for me.