I can give you a really inexpensive alternative... you'll be able to hit 16x20 for under $200...
Home Depot sells fluorescent blacklight fixtures - complete units with power supply, ballast, and BLB bulb for about $17. The bulbs are about 18" long. Get at least 6 of them, and one or two surge protector strips to plug them all in to, and then mount them to a piece of plywood, spaced as close together as you can make them. You can then hang this piece of plywood under a shelf, and place your contact frame below it on another shelf. I did mine on an IKEA IVAR shelving unit which has adjustable shelf heights, and it works quite well.