[LoneStar]

This looks like another viable option for a dimmable t5 HO ballast:

Mark 7 0-10v Electronic Dimming Ballast
RZT-2S54

http://advancetransformer.com/upload...Electronic.pdf
(page 14)

OR

Sylvania 49673 QT2x54/120 PHO-DIM

http://www.sylvania.com/content/disp...m&id=003678766