How do I get comps from off-market deals not on MLS?

[Peter Tverdov]

I need to pull comps soon in order to increase the odds of meeting appraisals. I know of several properties in the same area where I'm trying to close a deal, where a house closed and transferred ownership. However, nothing shows up on the MLS as being closed (yet - it's been over a month) because it was an off-market deal (FSBO) and nothing shows up yet on the tax records (that takes 3-6 months I would say). Any ideas how I can pull comps to show an appraiser that these houses DID indeed close and the prices are bonafide?