I thought I'd see what Utah Trikes had:
Utah Trikes Catalog - Trikes, Upgrades & Accessories; Trike Storage and Transportation
The "Sea Sucker" is interesting, but I'm not sure I'd do it unless I had help.
The Sunlight Recumbent Hitch Rack may well be what you're looking for though, if it fits your trike.
I can't make heads or tails out of some of the other racks they show.