Good news - a grower with 4 acres wants me to raise about 6,500 additional starts! That means more lights, space, $ and satisfaction.
We built a six-level light stand with 17 fixtures and 34 T-12 bulbs (cost for materials <$300). It can hold 24 1020-size trays and is filling up fast!
I'm using a lot of 288 plug trays, so theoretically this setup could hold >6,900 seedlings simultaneously. Of course they can stay there only for a couple of weeks, then it's transplanting time and moving to a makeshift greenhouse.