Thinking back to my A4 in my prior E-27, and I think 7 feet is going to be a really tight run on length. You won't have any spare cable to make any nice arcs etc. Try to visualize how far down and then forward the cable needs to run, and I think you'll use up 7 feet before you get there, or darn close unless you just pull it in a straight line. I know the Moyer cables (at least there long one) talk about stainless inner wire, which is nice on a boat, but you could certainly get by with a standard cable. So, just doing a google search for a "15' choke cable" yielded this right off the top - no experience with the vendor, but the price is right and I think it would be long enough:
http://www.rustrepair.com/part_numbers.htm?r=fr&pt=17415
Also, if you google "stainless choke cables", at first glance, it looks like you will find them out there for less than the $70 Moyer wants for his 20 footer. Not to put him down, but I was taken a bit back by the price.
