The short answer? Yes (for some estates without a filing requirement).
The slightly longer answer?
The IRS recently issued Revenue Procedure 2014-18 which:
"...provides a simplified method for certain estates to obtain an extension of time to make a "portability" election under §2010(c)(5)(A) of the Internal Revenue Code, by which a decedent's unused exclusion amount (deceased spousal unused exclusion amount, or DSUE amount) becomes available to apply to the surviving spouse's subsequent transfers during life or death."
The extension is limited in scope. For example, it only applies to estates of decedents who died after December 31, 2010, and on or before December 31, 2013 (among other limitations).
But it's better than the alternative. Previously, the only method of relief was to pay for a private letter ruling from the IRS.
Interestingly, the IRS decision is based in part on the Supreme Court's (SCOTUS) recent decision in United States v. Windsor, 133 S. Ct. 2675 (2013), which struck down §3 of the Defense of Marriage Act (DOMA).
A complete copy of the Revenue Procedure is available on the IRS's website, here: http://www.irs.gov/pub/irs-drop/rp-14-18.pdf
[For information only; may NOT be relied upon as legal advice.]