"I know some pretty dedicated people. But I can't think of anyone in a right frame of mind that would actually welcome the experience after a week. Its going to be really tough to find someone willing to do this."
You obviously don't know any dedicated people, or many people at all. I could walk around my office (I work in the aerospace industry) and find easily 12 people willing to do this. I would be one of those 12. If I went over to Johnson Space Center to ask, I would have people beating down my door to go.
Here's what you don't get: some people do things for the sheer thrill of exploration. No other reason. Some people realize that the earth is 6 billion years old and they are going to die in 50. Whether they die now or then isn't that big of a difference, really; but if they can do something dramatic in that time versus "just getting by" then their time on Earth actually meant something.
Also, it isn't like we'd be sending them in a sensory deprivation chamber for 6 months. People already spend 6 months up in space stations, and the vehicle we send to mars will probably be built up over time in orbit so it can be much larger and better equipped. They'll have computers for movies, email, internet (the lag will suck), and games. They'll have mandatory exercise periods, scientific research to be done, food cultivation work to be done, etc. They will also go as a team of 6-12 people, so your notion of them having "no one to interact with" is moronic. Even when they are all the way out at mars, the lag is only 28 minutes so emailing isn't that bad at all.
You seem to completely forget that just 100 years ago people wrote letters back and forth that took weeks (not minutes) to be returned. You seem to completely forget that just 100 years ago it took people weeks to get from Europe to America. Even today people will sail SOLO from Los Angeles to Hawaii, which takes around a month. Every year people solo sail around the earth for 120 days nonstop in the Vendee Challenge, which is 4 months completely alone where people die on a regular basis.
Hell, people climb and die on Everest every year and that's already been done.