need to carry my Zappy

Try versahaul.com. They are a bit overkill for your needs, but they are built for exactly what you need.

If you PM me I just might be able to give you some info on a lightly used versahaul that is no longer being used.

Harbor Freight

Ever heard of Google? Try searching on Scooter Carrier.

50 bucks at TSC

They make about 20 different types from $40 to $200.
This is but one place that sells them. Cost of shipping is high though. Auto Parts sell them or will order them for you so you don't have to pay the shipping. TSC always carries them.

http://www.discountramps.com/cargo-carriers.htm
Scroll all the way down the page there are some good ones near the bottom. There is one with a ramp but its about $300.

The one pictured above is attached to my toad and I've had over 400 lbs on it. You could buy a set of Rhino lightweight ramps to get the bike up AND use them to level your RV too!