"Is it possible to recover the $10K of BASIS in Traditional IRAs, if all five of the $2K NonDeductible contributions were made in 1994-1999?"
That could be problematic given that the 2011 Form 8606 reporting the Roth conversion did not include this basis. One could request a Private Letter Ruling to determine how the IRS would react, but the fees to do so exceed any possible tax savings. If you have combined state and federal marginal tax rate of, say, 33% averaged over the years you will be taking distributions, reconstructing the basis would save you about $3,300 in taxes.
