I'm also late night gamer, usually between 10pm-3am central.
What I do is, or course, put my seek up. Then I /sea all whm 43-47. That way I can see if there are any in the area, and also see how many parties are going at my lvl. If I can't convince one of them to start a party with me, I then send /tells to the ones in a party. <Hello> <Excuse Me> <Invite To Party> for replacement <Thank You>. A lot of times they will keep me in mind, and send an invite when another DD leaves.
If I'm able to find a whm that is willing to start a party, I then go to tanks. First paladin, becuase I prefer them over ninjas. Then ninja, and last, and least war/nin.
If all else fails I sub thf, put in my search comments that I do have a war sub, and go farming.
I've really found that the lack of other people seeking that late works in my favor. Even if someone hates drks they'll usually invite me for lack of other choices. Plus I've been gaming at those hours for nearly a year now, so a lot of the late night people either know me, or recongnize my name. I don't have top of the line gear, but I'm getting there, and I know my job.