Ooo difficult one that. There seems to be a number of deals with a Haicom 203E and a mount. I have used that model and didnt find it to be that great, took a little longer to regain a fix than my Fortuna clipon. Have just spotted these
http://www.gpsforless.co.uk/bundles....Rikaline%20GPS
http://www.pocketmapstore.com/rjtops2coca.html
My Arkon mount does not have a RJ12 port on the top like the new ones do, but you can get adapter cables to go from RJ12 to the PS2. My advice would be to ask the supplier of the Arkon mount if they do the Rikaline 6010 and the adapter cable for the Arkon mount. Also might be worth posting on
http://www.pocketgpsworld.com/
See if anybody else has done it with that mount. Ther are several people running Brodit mounts with a varity of receivers, but they tend to cost quiet a bit more.