I used the Penguin 15,000btu roof top. Made a wood platform for it. On the air intake, had an 8" plenum made. On the cold air outlet, attached a 6" diameter flange. Took the top hood off. Had a 6" plenum made for the hot condenser air and covered the condenser coils with plywood held with a single 3/8" stud through drilled to the chassis. Attached a 3/4" flange on the drains and plumbed for draining condensation. Had to pull the wiring out from the inside of the evaporator to have it available on the top of the machine.
It took a bit of designing and about 8 days of construction to do. The reason-the roof A/C is about $800. The basement air is close to $2,000 with the same equipment.