My routine for taking flats is kind of cumbersome and I'm thinking about getting a flat panel to do them inside at my convenience. I seldom disassemble my optical train so dust motes are not really something I'm worried about - mainly just want to get well-calibrated flats.
I'm looking at this thing from B&H. It should work, right? The ones designed for astro seem expensive for what they are or (such as with the Gerd Neumann ones) use a 12V connection that doesn't connect to any of my power supplies.
Alternatively (for another $50 or so) there's a Pegasus Astro flat panel that'll still work with all of my OTAs.