I was afraid of that

Ive witnessed your crafty work and figured this would be no exception, my apologiez. I have no clue as to how your setup will be, if it will have a canopy or an open top. If you wanted an open top that drastically reduces your options of course. Assuming this is your obsticle as far as fixtures are concerned I honestly cant say I could find one cheaper, but havent tried either

But, you still can get the best light sources over an open top, it just depends on how resourcefull you are, or of course, how deep your pocket is.
There was a person here forgive me for not remembering who, but had a lumenarc mounted on a support beam over his tank that also appeared to swing in a 360 direction if desired. It basically looked like looked like an upside down "L" that was mounted to a stand on the floor. I was very impressed by how simple, efficient, and "clean" it looked, kudos again if your reading this!

They also sell mounting racks to suspend above your tank, or you can use hanging wires. Get a Lumenarc mini from
http://www.pacificgardensupply.com/products.asp?cat=2
and you have the potential for the best MH light available
or for T5's next to the best of the best would be
http://reefgeek.com/products/categories/lighting/104193.html
You can also buy legs if you wish to put on your aquarium, or you can suspend. You can also pay the difference and have them swap out the reflectors for Icecaps giving you the best T5 fixture money can get you. Basically anything you can do to make your equipment as retro as possible only gives you the potential to always have the best for the life of you interest in this hobby. Lights are easily replaceable, true. But what happens if you get a lemon, and your ballast burns out? Or just burns out from normal use like they all eventually do anyway? Deal with the downtime sending it back for fixing? Buying a new one? Or, busting it open and making yourself go the expensive rout of retrofitting
But no way or piece of equipment is better than the one you chose that works best for you!
-Justin