I'm looking for a plan or photos of a device that'll let me lift a
250-300# pallet from the floor, can be pushed outside, and will let me
set the pallet in a semi trailer. The object is to avoid paying for
lift gate services.

Something like this?
http://www.northerntool.com/webapp/w...Id=7 87&R=787
("High lifting pallet truck")
I assume larger wheels could be installed if the stock ones are too
small for use outside.
Andy