I'm not sure this directly addresses your situation but it certainly has some application:
It seems to be common and accepted practice to use offers (specifically, an offer letter so there is actual proof) to get an increased salary out of your current employer. When I was working as a PACS Administrator at Rex Hospital, I was on call 24/7 and was getting burned out. I thought, erroneously, that getting more money would help the burnout and spoke with my boss about it. "No money is available," "It's just not possible" were the responses I received.
Shortly after, I was sent to a large industry convention in Chicago. And took copies of my resume.

Three weeks later, I had an interview with Fujifilm Medical Systems and shortly after that, an offer letter.
I presented my manager my notice of resignation and he wouldn't accept it, claiming he needed me to give him two days to match the offer. Oh-my-gosh-how-amazing! He suddenly found the money to not only match what I had asked for before, he even found enough to beat Fuji's offer. I made my decision and five years later, I can still say I have absolutely no regrets for making the choice I did. I told him I wasn't interested and submitted the resignation.
I guess my point is that money (as in your salary or hourly payrate number) isn't everything. I learned from that experience the hospital would never pay me what I was worth (not just my opinion but Fuji's as well) unless I had some real leverage. That is not the environment I wanted to be a part of. As I mentioned above, I have absolutely no regrets in going to Fuji as the pattern of raises I've enjoyed there have quickly outstripped anything offered to any regular employee at a hospital. Past that, Fuji offers a number of other very important benefits; profit-sharing, health, dental and disability, to a much greater degree than the hospital. Oh, yeah...and NO PAGER!
