I saw your request for a rotor control unit on the mailing list. I was in your shoes a year ago or so and chose to go with the ERC-M USB unit:
http://schmidt-alba.de/eshop/product_info.php?products_id=18 http://schmidt-alba.de/eshop/product_info.php?products_id=18
It is a kit that went together VERY easily and I can’t over compliment the company and the support offered by its founder and CEO. I would also suggest that you read the reviews at eHam.net:
http://www.eham.net/reviews/detail/8210 http://www.eham.net/reviews/detail/8210
All 5/5, really hard to beat. I also want to state that I have no connection with the company at all. I am sure there are other products out there that are fine, but I can tell you for sure that this product will work great and if you ever need support, you will get A-! support.
Good luck and Best Wishes, Fred - KF4FC