Would they eventually get a tan, or even a sunburn? Would they turn to ashes instantly, or would it take time, so it'd be more like dissolving into ashes?
Well, given the high likelihood that vampires got that particular trait from people who suffer from albinoism, it would make sense that sunbeds would pretty much instantly vaporize them. Radiation is radiation, no matter its source; the only reason we can survive the constant solar radiation we get from day to day is because our atmosphere reflects most of it.
I don't think that artificial light or radiation would effect vampires the same way that the sun would, even if it basically has the same effect on people. Vampires are mystical creatures, it just sounds kind of lame that they could be killed with a sunbed.
Sunbeds may have the effect of the sun, but they aren't the sun. Sure, they may burn quickly, but I doubt it'd kill them. It just wouldn't make sense, really. In my opinion, really.
The sun is *special*. Sunbeds, although they are still radiation, would most likely affect vampires, but not in the same way the sun can.