i came across this today: http://www.conrad.at/ce/de/product/5...9AEF6.ASTPCCP1
a r7s-socket uv-lamp, which should fit into a cheap flood light (not closing the glass cover it came with, to not add any uv-filtering, i guess). it costs about $20 and i'll pick one up soon and see how it prints.
there's a data sheet available (in english too), but there isn't much info apart from "emits strong uv-light in close proximity. take care".