Seems like a workable set-up... might want to consider putting some serious weight in the bottom tray of the cart (cinder blocks?), as it looks like it may be somewhat top heavy with the bike in place.
zorgitron, check out Handy.com, they manufacture the industry standard for Motorcycle Lift Tables, found in use everyday at bike shops.
They sell for less than a grand (plus freight), and are worth every penny! I bought two of them back in 1990, for my motorcycle/snowmobile dealership service department... no back problems whatsoever!!!