I purchased my Sunlight Supply Tek-T5 Retrofit kit from OA this summer. Unfortunately I had to wait about a month for the bulbs to come in from Germany. I'm not sure what the bulb selection is like now at OA though. If you do decide to by from the Yank's, than you might want to check out this site as well.
http://www.aqualuxlighting.com/retrofitkits.html