Reasonably complete infrared spectral database with data in CSV form?
First off, I would think you could fairly easily design some data extraction tools for the AIST database. After all, the X and Y axes are standardized (i.e., $4000-400 \mathrm{cm}^{-1}$).

Beyond AIST, you can find machine-readable JCAMP files from the NIST WebBook. There are supposedly ~16,000 spectra, although you'd have to script some way to download them one-by-one.

I think a better bet would be to purchase a database:


Bio-Rad sells an IR database. A quick look now indicates that it has ~235,000 spectra and I'm sure it's in an accessible format.
NIST sells a smaller database ~5000 compounds in JCAMP format.


A quick search also turned up:


IR Spectra.com - claiming ~140,000 spectra in various formats.