You can still get VHO bulbs from Champion or order directly from UVL. A few locals got some Super Actinic from Champion a while back in a group buy. They are twice the wattage as T5, half the bulbs, but also twice the output if you can get them on good reflectors, which you usually cannot so people wrongly think that they are less efficient, but it is a reflector thing, not a bulb and ballast thing, but it is real issue unless you can make some good reflectors or find some older good ones. The internal reflectors in the VHO bulbs help, but not as good as a good parabolic reflector. IceCap 660 can run T5 bulbs at about 96w for the 48" versions and they put out some good power. Bulbs definitely need changed at a year if you overdrive T5s, or whatever you consider half of normal life - for me, normal is 24 months, so I would change them at 12.
@Big E used to do this, but I don't know if he still does anymore... 4 bulb setup has more output than a 6 bulb, but not as much as an 8, or the one that I saw did. In the end, if the reflectors are good, you don't save or miss much with whatever you do with similar wattage, but the reflectors can be a big deal with VHOs and retrofit T5s too.
The reason to use VHO is if you just love the look and pop of the Super Actinic or Actinic White since nobody has gotten these the same yet. If you don't have any love for these, then it might be more trouble than it is worth.
People still want IceCap ballasts if you want to give them away and not waste them - they are still in use by people who love them, want 6' bulbs and have the good reflectors already.
