There's a guy who sells them on ebay - he bought out UE or maybe it was the guy on ue, bnighs, not sure, don't remmber. He tried selling them on the UE BST, but he doubled the price on them and no one bought a single one. He 's slowly selling them off on ebay at $40 a pop. Strobe is still around, but he's not making them anymore or his slippers.

Like Neil suggests, easy enough to make your own.