It seems I'm a little late to the party, but...I would second Greg's advice to buy used. If you are patient and willing to drive a bit, used Nuarc models can be found for pennies on the dollar. When I was looking for a UV light source I originally passed on the idea of a Nuarc because I assumed they would break the bank. When I actually started looking I ended up finding a number in the $150-$300 range. They might not pop up every day, but cheap ones are out there. If you find one on craigslist or a different classified service don't be afraid to wheel and deal on the price...people aren't exactly standing in line to buy these things.
The Nuarc 26-1ks and the 26-1k are the most common models you will find (in the states). The 1ks uses a metal halide bulb (which sell for $125+) and the 1k uses mecury vapor bulbs (generic replacements go for about $40).
As far as new models are concerned - Amergraph makes a model that they specifically recommend to alternative printers.