Woodrat Dovetail/Joinery Jig
The Woodrat is perhaps the most unique dovetail jig on the market, and appears to have the largest learning curve. I have not used the jig, but it gets high points for versatility and creative capacity. Setups appear to be more complex than typical jigs. The Woodrat runs around $500.
Click this link for Woodrat Dovetail/Joinery Jigs for sale on eBay