What are the downsides to purchasing four foot shop lights and lamping it with Kino tubes as a cheap way to light a small green screen? I have Kinos but was asked this and didn't have the answer other than the light output would be less efficient.
Of course you can do this and have the benefit of the pure photographic colors of the KF globes (in fact I do so in my shop), but when used with the proper KF ballast the light operates at double the frequency, both doubling the tubes output and eliminating flicker at off speeds.
I am using commodity 4-ft "shop lights" from Home Depot just for lighting green screen. Be SURE to get the kind with high-frequency electronic ballasts vs. the old traditional strobing, buzzing, heavy 60Hz magnetic ballasts. You can get very inexpensive fixtures at commodity outlets with HF electronic ballasts that function just like Kino's ballasts.
Note that the traditional fluorescent tubes have a horrible green spike in their spectrum which is why they are mostly unsuitable for shooting quality video. HOWEVER for simply illuminating the green screen (NOT lighting the foreground actors/objects) that green spike turns into rather an asset. :-)
Spending extra $$$ on balanced-spectrum tubes seems like a waste for dedicated green screen illumination. OTOH, if you needed to use the light fixtures ALSO for more traditional kinds of lighting, then balanced-spectrum tubes would be necessary.