Thanks to Lenn Harley at Homefinders.com for bringing this to my attention.

For those homeowners with a VA loan who find that they owe more than what they can sell the home for, the VA has what's called a Compromise Sale.

From their web site:

If the borrower is unable to sell the property for an amount that is greater than or equal to what he/she owes on the loan, including closing costs, VA may pay a “compromise claim” for the difference in order to allow the private sale to go through. The borrower can sell the property to a buyer who gets his/her own financing or to a buyer who wants to assume the loan. However, with a compromise assumption, the lender does have to agree to have the amount of its guaranty reduced by the amount of the claim payment.

 This program does not automatically relieve the borrower of all obligation for the shortfall. However, they may be able to wrap the deficiency, closing cost assistance for the buyer and the real estate commission into a loan at a very favorable interest rate.

There are detailed instructions for both the homeowner and the real estate agent on the web site. It may not be the perfect solution, but it'll be the help some families need in order to move on.