Wow.
ThinkGeek had some new in box Dreamcasts for sale. $99 each.
...and now they are all gone.
http://www.thinkgeek.com/geektoys/games/ba52/
However, you can sign up to be emailed if they happen to get any more in.
Wow. These sold out very quickly. I think the the TG store is probably kicking themselves for not charging more.
(And yes, I know that you can get NIB Dreamcast's elsewhere on the web for the same price. I posted this to note how quickly these things sell out when major sites report on the sale (Kotaku, Cheapassgamer...ect)