Here are a couple. i've had good experiences with all three vendors. I looked at HO T-5's, but the prices were out of my ballpark (little league).
I think most vendors are going with the NO T-5's instead of the fatter t-8's, etc. I just switched since they were more efficient.
Back to HO T-5's...
http://www.drsfostersmith.com/produc...?N=2004+113175
http://www.petsolutions.com/Lighting-C-33-C-.aspx
http://www.thatpetplace.com/Products.../Shopay00.aspx
Try Big Al's Online too.
Let us know what you decide to go with...