There's a lady (Equestradreams Tack??? I think) that sells them on LB last chance auction and on ebay. Just have to watch. If not, most mini tack dealers will sell them. Look on lilbeginnings.com and mini horse links. Theres a bunch of tack links there.
Depending on the size of your horse, and his/her eye (imo) SStack.com has some gorgeous ones for full size horses that may work well and be "different" from what many others are using. I have bought a couple from them over the years with gold or silver horse head silhouettes on them and they are gorgeous. Also, when I ordered some of my show halters from Victor, I got his (hand made, beautiful!) conchos put on some of them as well. They are very delicate and extremely classy.
I've used the SStack ones for biggies on my tall B gelding (37.25" or so) and like them, and the new ones SStack has that are similar are actually a little smaller (1/8" smaller) so would work on even more minis I think.
Here's Bacardi (B gelding) in his SStack "biggie" conchos: