Here are a few two-shelf options. I'm not sure what the fixture descriptions mean; if you want four bulbs per shelf, I'd call and make sure they have that.

Alternatively, it's easy and cheaper to build a rack from scratch. You can modify the design for the number and height of shelves you want.

I adapted a wire kitchen cart to serve as a two-shelf plant stand. (When it's not seed-starting season, the lights can be moved up and out of the way or removed and stored.) Buy sliding fixtures with knobs (the part numbers ending with -S). The inverted U-shaped supports that the knobs attach to are available separately, and inexpensively.