I have a few 4' T12 fixtures I got at a habitat store for $5 each. I plan to put some quality T8 ballasts in them. I don't have any facts but I get the feeling those cheapo fixtures use a chepo ballast that is causing the RFI.
The instant start ballasts are real hard on the lamps so I plan to use rapid start models. Every time you turn on any fluorescent lamp a few hours are shaved off the life of the lamp.
I plan to put a few medium base sockets so if I will only be out there a few minuets I can use incandescent lights and not fire up the T8s. On the second switch I will have the T8s.
For my shop I scored some 400w metal halide fixtures for $10 each. The are only 5 years old and look hardly used. The plastic diffusers are cracked so I think that is why they were donated.
They are high bay lights though but for the price I can live with the shadows.