looks like more of a lenz to me. Something like that is made to disburse the light more sideways then anything. The 6 in pipe will work, cause remember when you open it up its now 12 in, and if you spread it out a little... well it gets bigger. I used a peice of stock ducting i found in the hvac dept at lowes. Just bent it up to the shape i wanted, some hooks, and chain. Tossed the light in and bam. If you want to make a cool tube, how bout just a vented hood. Bend yourself up a trapaziod and 2 end caps, then vent it. If you got 2, put them in line with each other and away you go.
Dont kow if we were talking cfl's or not, but anyways. Seen some guy on here ( cant find it now ) take a regular dome reflector, the cheap ones you get from the depot. Then cut 4 lines from the bottom to the neck, then bend em up. Put in 3 sockets that have the recepticle on the side, add 4 bulbs with plug in adapters, and presto 4 bulb cfl reflecter.