I carry the full line of icecap lamps. (not on site) I run them on my prop tanks. No par readings for you though, sorry. They are made by UVL for IceCap. I'm not to sure about the thicker filament, but I know they are specially made to be overdriven by a 660.
The IceCap T5 lamps are made by UVL for us. They are made for our specs and do include an extra heavy duty filament. This is done so they can handle the additional output of the 430 and 660 ballasts. But, they can also run on standard T5HO ballasts.