Just a tip, but check with your local credit union. Here they are running 4-5% APR range for secured loans. Also, it is always more beneficial financially to sell and buy than it is to trade. Good luck!
I have to agree with Tenn. Best to sell bike you have and use money towards new bike. Patience is truly working in your favor. OP said you sold used cars and such? Should know this. Harleys are no different. Personally I'd sell current one before I'd ever try to trade up.
I have extremly bad credit and I still got 10.99% interest from harley finance..
HOWEVER I ended up holding off and bought a 07 nightster with 3k miles for 5.5k yesterday...so deals are out there. I would keep looking unless he just REALLY wants a brand spanking new one.
I ordered a 2012 1200C two months ago. 11,432 € in total with a QD 14" windshield and heated grips, got 4% off the bike's price by the unofficial dealer, plus 10% off on the QD WS and grips, got a full loan at my bank, interest will cost me almost 1200 € on a 5 years long loan. Bike should arrive this week...