It bites at 56, too. :)
I just turned 50 and so far not having any problems...I average about 1 date a month.
For a very interesting take on "settling" check out Lori Gottlieb's book "Marry Him: The Case For Settling for Mr. Good Enough." Also, Google Evan Marc Katz--he discusses this a lot.
I think one of the reasons we are "pickier" when we are older is that we have settled for less in the past and it didn't work very well. Also, if a man in his 50s still doesn't have his act together, it's unlikely it will happen. It's not like we're in college anymore and your entire life is in front of you.
You might need to be more flexible on the tall thing, though.
There are some things that I think it's good to be flexible on (maybe height but I can't really relate to that since I'm very short so basically all guys are taller than me--for my SIL who is 5'9", a tall guy is important).
Most of us
I have a male friend who is almost 50, divorced for 6 years after a 20 plus year marriage, and grown kids.