Korie, I have personally known people with MS, Lupus, brain tumors, mobility challenges and neurofibromatosis who are with fantastic partners, so there is definitely hope for you, too. Around half of those folks were with their partners when they were diagnosed and the others met their significant others after they had been living with these issues for a while.
There is one way that having TN could actually work to your benefit: It will automatically weed out most of the nitwits, since they would never want to date someone who isn't "perfect". That will save you a lot of aggravation right there.
You are may be right in that finding a significant other might be more challenging for you than your average twenty something year old. There are a lot of otherwise perfectly decent people out there who might not be able/willing to deal with a partner's chronic condition because it's just too much for them for whatever reason.
Still, there is hope, tons of it, in fact. You seem really smart, funny and kind. You have been through a ton of stuff that would have knocked most people down, and yet, here you are, making the most out of life. This makes you a total catch, and somewhere out there is someone who will recognize that. This person is worth holding out for.
I agree with Crystal in that the internet is an excellent place to start. Perhaps Ben's Friends should start a dating service! (I'm not serious as they have more than enough to keep them busy, but it's a good idea, huh?)
Luke, if you have ladies chatting you up in the bar, I think you should give them a chance (says the gal who met her partner in a bar when a relationship was the last thing she thought she wanted). I understand completely that you don't want to burden someone else with this and I think that is very honorable. That said, this condition is so isolating that I think you should grab every opportunity to connect with the outside world that you can get. Plus, you never know if one of them might be the girl who doesn't mind at all about TN because she knows how lucky she is to be with a kind, thoughtful, decent bloke like you.
Good luck to both of you and to everyone else out there too.