both phill and I have rear decks. I put my V-max (~600 pounds) on the rack. I'm sure your bike is significantly hevier, but you could easily build or have built a rack to accomidate the weight.
as for the approach angle, i try to minimize how far off the ground my rear porch is when loading. IF i park in the city, i load/unload onto the curb. that changes things about 10" or so. If i'm out in the country (where i live) then it's pretty easy to find a hill you can back the rear porch on top of that brings it really close to the ground. Sometimes i can just about ride off of the porch without a ramp because it's just a couple inches fromthe ground. All it really takes is anything to raise your front tires higher than the rear.
this is not my bus, but is a good example of a simple porch construction. I think my and phills porch are pretty much the same as this one.