I don't think the arcadia MVB's are available in the US yet. If so lightyourreptiles.com is where they would be.
LYR's now has TWO kinds of arcadia
1st is the odd sized ones (22", 34", 46") are HIGH OUTPUT needing a high output lightfixture (just get the bulb and fixture from them, I haven't been able to find the T5 HO (I'm guessing European?) sizes anywhere.
2nd is the 'regular' sizes (24", 36", 48") that are T8 bulbs and take REGULAR (nominal output) fixtures.
While they aren't listed on the website yet Todd also has reflectors available that are REALLY easy to instal (just clip onto the bulb and you're set) and work great with any fixtures (shop light types) that don't come with a reflector. I can tell a noticeable difference in how bright my tank looks after installing it.
As far as the MVB's go from what I read recently they don't seem to be putting out as much UV as previously thought.
http://www.herpcenter.com/habitat-lighting/42625-zoo-med-powersun-mvb.html
Here is the link that was provided for me when I had questions about them.