I have the Maxxraxx rack very nice bit of kit, takes 5 bikes
I have not used it in years as the kids have grown up too fast and not interested any more, make me a good offer and it can be yours, recon its only been used less than half a dozens times.
This is the one I have, but mine bolts on to the swan neck removable tow bar so you should be able to tow at the same time, but never tried it!
http://www.maxxraxx.co.uk/bike_racks...max5_swan.html