I'm running shoplight fixtures modded out to 2 ballasts per fixture, to overdrive a high output T8 to 5000 lumens +. I use a Lithonia 1241CW fixture, and mod it with 2 ballasts, and I use carpet tape to fasten mylar to the reflector to boost the performance. This is quite a lot of work compared to buying a ready made T5, but then you can use cheap T8 lamps, and I reckon the illumination is in my garden 100,000 lumens over a 4' x 6' garden gives 5.000 lumens per square foot. Note that by building a solid bank of fluorescent lamps, the effect is like a "plate source", as opposed to a point source HID lamp, which follows inverse square, compared to "cylindrical source" of a single flourecent lamp which follows a simple inverse relationship, compared to a "plate source" which is a first approximation of natural sunlight (no falloff of intensity with distance, at the heights that plants grow on Earth). The result is that I can grow sizeable plants with this setup, compared to the
usual short SOG grows.
The above post is for entertainment purposes only, as I do not grow pot and do not advocate breaking the law.