A number of people had been asking about about how to purchase the Odin TCU separately to use with their Mitros+ flash units (which have the Odin transmitter and receiver already built in). But previously you had to purchase an Odin TX and RX set from around $330, just to get the transmitter unit.
I just spotted the Odin TCU available separately though in the Phottix Store, and for a very reasonable $165. With the Xmas discount that brings it down to just $148.50. At that price its worth having a second one just for a second camera etc.
B&H Photo and Adorama also stock the Odin, but do not appear to have the TCU available separately as yet. They stock the Mitros+ for $399 though (also $405 in the Phottix store with Xmas discount) so you could effectively have a very convenient Mitros+ flash and Odin transmitter set for around $550.