The problem is not only the bulbs but the fixture. The fixture has to manage the light produced by the bulbs. Its really amazing its so difficult to find a light fixture that's made to do what we want over a table.
My wife works for an architectural firm who has lighting experts and a lot of resources. The light we picked was from Axis Lighting.
http://www.axislighting.com/ Medio Picolo
The light holds 4 T5HO bulbs with a nominal 8' length over a 10' table. I'd think most folks would think this lamp is perfect but a light meter says not so much. I supplemented this with peripheral can lights which helps but causes an unsightly shadow under the rails.
If I were to do this over again I'd hang 2 - 8' fixtures holding 2 bulbs.
The very best light I've seen is sold by Gabrial Billiards. I believe this also uses T5HO bulbs.
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