Big issue is that, in general, the Government doesn't know for cost-type type contracts when the vendor has received their final DCAA audited rates for a given year. I may know that Vendor A typically receives its final rates in late August (for 5 years ago) because they send me a rate adjustment invoice on 1 Oct each year that I wind up paying with current FY funds since the funds valid for the POP cancelled on 30 Sept, but I don't know that there's an authoritative source I can use to find out if a vendor has received its final rates for any given year. So maybe the answer is that DCAA develop/maintain a database that is searchable by other Government personnel and shows only the following info - DUNS number, Vendor FY start and end dates, Date (if completed) that DCAA issued the rate letter. Then a CO/CS/COR could look up the company and figure out if a contract can be closed out. You'd still have to contact the company to get a copy of the actual letter but you'd be able to say "the DCAA website shows they issued your 2007 rate letter on 30 Nov 2011 so I'm looking for the final invoice for this contract"
I know of at least one vendor that is 8 years behind with DCAA. But I also know Government folks who will say they have to wait on the final rate letter because there was $100K in ODCs over the life of the contract and the vendor had G&A or MH on the ODC cost. That's when I ask if a Quick Close-out can be done because FAR 42.708 gives dollar thresholds for the unsettled indirects.