Small update.... I have switched suppliers. The retrofit kits I was getting - turns out to get the rebate from my utility they must be UL listed and those other retrofit kits were not. I actually just ordered enough to retrofit ALL of them from
http://www.prolighting.com
I actually got them to give me a custom quote since I am ordering over a grand in stuff. Rick from there took good care of me and even matched prices on the lamps I found at 1000bulbs.com and the ballast prices from Warehouse-lighting.com. ProLighting does not even normally stock Eiko lamps but they are a dealer for them. Essentially I am getting the Epco 14065 Retrofit Kits (UL Listed and even Made in the USA) for $9 each, a couple of bags of the quarter turn clips (Epco 14085), the Espen VE254MVHRP ballasts for $18 each, and on the lamps I'm going with a combination of the Eiko T5HO 6500k in both 54 watt and 49 watt. Since the 54 watt ones are so dang bright I figure I can save a few bucks on energy usage and make every other one a "energy saver" 49 watt lamp. I'm getting the lamps at $2.70 each. I cannot of course guarantee ProLighting will give you the same pricing. Mine is based on a decent sized order. But you could always get the lamps from 1000bulbs, the ballasts from Warehouse-lighting, and the retrofit kits from ProLighting. I pretty much asked if they would match the pricing so I could just order everything from one place instead of 3 different places. Also - the Eiko lamps are rated for 25000 hours and have a CRI of 85 and the ballasts have a power factor of .98 which is pretty dang good!
Also keep in mind - these are for your run of the mill 8 foot strip fixtures which should be about 4.24" to 5" wide. Most existing fixtures just have a plain white cover over the channel which will reflect the light pretty well. Mine actually all already had big wide reflector covers - still plain white though. I needed the extra quarter turn clips because the existing reflector/covers were designed to only use one clip in the middle - the outside ends slipped into a notch on the original end brackets. So I'm having to drill a hole in the one end for a second quarter turn clip. My utility also re-classified the rebate category for the retrofits I'm doing and the rebate went up to $20 per fixture.
All in all - (I do have a scissor lift which makes things a lot easier) the full conversion of one fixture including taking the existing covers back down to the floor to clean them and drill the one hole takes about 15 to 20 minutes each. In the end I'm now at about $34.50 (all parts and shipping) per fixture to retrofit them less the $20 rebate putting me at about a real end cost of about $15 per fixture AND if all 50 are on (and using one 54w and one 49w each versus 2 old 2x75w lamps) I'm also saving about 2350 watts of electricity or about 47 watts per fixture.