I bought, at one of the big stores, some of the 2' x 4' fixtures designed for T bar ceilings. As my ceiling joists were 24" oc, the fixtures wouldn't quite go between the 2x4 joists. My ceiling is drywalled so I laid out the length and cut between the trusses (joists). I then made a frame of 1x2 and fastened this through the drywall, leaving enough space for the lip of the fixture to fit. Once in place the fixture fit on the surface mount frame and fastened up easily. I think the fixtures were about thirty bucks for a four bulb fixture.