I don't know if the rules are going to change with the new ATP laws or not, but this is what you guys are looking for...
FAR 61.39.b.1 & 2 (emphasis added by me):
"(b) Notwithstanding the provisions of paragraphs (a)(1) and (2) of this section, an applicant for an airline transport pilot certificate or an additional rating to an airline transport certificate may take the practical test for that certificate or rating with an expired knowledge test report, provided that the applicant:
(1) Is employed as a flight crewmember by a certificate holder under part 121, 125, or 135 of this chapter at the time of the practical test and has satisfactorily accomplished that operator's approved—
(i) Pilot in command aircraft qualification training program that is appropriate to the certificate and rating sought; and
(ii) Qualification training requirements appropriate to the certificate and rating sought; or
(2) Is employed by the U.S. Armed Forces as a flight crewmember in U.S. military air transport operations at the time of the practical test and has completed the pilot in command aircraft qualification training program that is appropriate to the pilot certificate and rating sought."
This reg actually allows you to take the ATP practical with an expired written REGARDLESS of how long it's been expired or your current employment history. You could have taken the ATP written & then flipped burgers at McDonald's for the last 10 years, then (provided you meet the other qualifications) go through a 121 or 135 company's approved PIC training program and be allowed you use your old written.
I actually just used this reg myself. I was a Mesaba -> Pinnacle F/O who never got to upgrade. I left a few months ago for a 135 job. They sent me through their approved PIC training program (administered by FlightSafety but developed by the 135 operator & approved by the FAA) & I was allowed to use an expired ATP written, despite the fact that I had taken it about 5 years ago. Now I've got an unrestricted ATP.