Looks like there may very well be a new(er) player: induction fluorescents. The watt/lumen outperforms the best T5s and lamp life is 5 to 10 times as long. My big concern is they are very likely way too expensive for the hobbyist. Perhaps in a few years this technology will become the default and prices will drop accordingly. I requested a quote.

I have no affiliation, but here is their ad copy:

Everlast Induction Lighting

Unmatched 100,000 hour rated bulb life!
Replace Metal Halides 1-for-1
Reduces energy costs up to 60%
Lowest lifetime cost of any light source
5/10 Zero Maintenance Warranty Standard
6/10 Zero Maintenance Conditioned Spaces Warranty
Excellent Lumen Maintenance, 70% for 10 yrs
Universal voltage standard 120/208/220/277
Unlimited On/off cycles with Instant Re-Strike
Operates 800° cooler than HID sources
Balanced 5000 kelvin 90+ CRI output
Low temperature starts to (-30c)
Dimming options for all fixtures How EverLast® Technology Works

Profiled heavy-duty extruded aluminum housing and crystal clear tempered glass lens. Features an anodized aluminum reflector and gas-tight silicon rubber seal made for wet locations. Ideal for retail, manufacturing, outdoors, wet or dusty locations. Flexible mounting brackets allow for this fixture to be suspended or wall mounted with angled adjustment. Available in 100, 150, 200, and 400 watt versions. 100 watt emergency ballasted for power outages is also available.