FWIW, I run four nearly identical Buck/SRI 910 GCs that have a TCD and FID in series.
I've yet to actually have a need to dig in to one, but each has a built-in air compressor to run the FID. I'm not sure what sort of compressor or how large it is, but it's a beautifully elegant solution. The baseline is a bit higher than I'm use to seeing on zero grade or UHP air, but it otherwise works perfectly, gives a stable baseline, and I can't hear it over the oven fan in the GCs.
I'm running a 5890 now off of a cylinder, but that's just until I get around to plumbing it into house air. Admittedly our house air system is geared toward scientific instruments and, among other things, supplies air to the AA, purge gas for probably a half dozen FTIRs(I run three off of it, and there are a few others scattered around in research labs), and runs the pneumatics both on the MALDI-TOF and on all four of our NMRs(400mhz, 2x500mhz, 700mhz). Even though it has HC and water scrubbers in the distribution room, it will still get a secondary set before running into the FID.