I searched, I read, I got tired.....
Simple question (LOL!):
You might think so, but...
What are the brightest (non-LED) 4' flourescents made?
Are you talking about the tubes themselves? Or the fixtures?
If the former, there is a F48T12VHO type
http://www.1000bulbs.com/product/6357/FHO-V48CW.html which can produce ~6,600 initial lumens; but their MEAN lumens spec is not all that good at ~4,600, and they are problematic in other ways (expensive, hard to find, few fixtures support them, relatively short life, they need Hoover Dam to feed them, REALLY crappy CRI, etc.).
The brightest COMMON 4-foot tube is the F54T5HO
http://www.1000bulbs.com/search/?q=F54T5HO, which typically produce about 5,000 initial lumens, and use only a nominal 54 watts to do it.
If you are referring to the fixtures, it depends on the TYPE of fixture which is appropriate to your space (in particular, the mounting height which can/must be used); but in general, going "brighter" is just a matter of cramming more tubes into each fixture (which is very rarely really a good idea; but you asked).
Secondary question: what are the brightest - including LED?
Anybody's guess; there are way too many variations out there to even begin to keep track of. But hype notwithstanding,
in general, LED is
NOT particularly brigher or more efficient than GOOD fluorescents.
Tertiary questions - what are the most economical brightest flourescents?
For all intents and purposes anyway, F54T5HO. Common ones do up to about 93 lumens/watt, for about $3.00 per tube.
HOWEVER... All the foregoing aside, "brighter" may or may NOT be what you really need. And at least usually, F54T5HO tubes are
too bright (even when used only two at a time) to produce the best overall results unless you can mount them significantly higher than most folks can manage in a typical residential garage.
I currently have a mix of "daylight" and "soft white" tubes,
That's generally not a good idea. Pick ONE color temp you like, and stick with it.
but they are really dull when cool and not bright enough when warm. I'm always needing extra halogen spots on my work - especially as I get OLDER....
We'd need to know a LOT more about your workspace, and your current lighting, to make any sort of intelligent recommendation. But again, if this is a more-or-less normal residential garage, or anything which even remotely approaches same, the odds are you don't need BRIGHTER lights; you need MORE lights, with better placement of each one.
Yes, I was looking at one at Home Depot yesterday. Some may joke at me saying this but it looked extremely bright. Almost hurt my eyes to even look. I looked at the reflected light on my hands and it was the brightest out of everything I saw.
Just this is the part that concerned me. Why do they say 15' min height recommended? Will it be too bright with 10' ceilings?
Because that particular fixture is apparently a "High Bay" type, which means it is designed to focus most of its output straight down, with relatively little spread out to the sides. That in turn means that, to cover a decent amount of floor area, it MUST be mounted relatively high.
They also say "Not recommended for surface mount installations" which is what I want to do.
That's another matter, and it relates to heat dissipation. If a fixture is not explicitly rated for direct surface contract, you MUST leave some minimum amount of air space (could be a couple of inches, could be a couple of feet) between it and the ceiling, lest the fixture overheat and therefore die prematurely (or create far more ominous problems, which I will leave to your imagination).
