Does it exist? I'm running a wind tunnel 6 on a speed controller, and it works great, but I'd like to turn it down at night. It's a little noisy. I'd need a timed variable speed fan controller. Probably digital. It would need an internal clock so I could sink it with the cool tubes. (overlap of course)
I don't think it would be too hard to make. A few diodes, a rheostat, 2 power supplies, and 2 timers.