I believe every major airline has some kind of RTW dealie, plus there are travel agents that specialize in RTW fares.
If you start in another country, chances are quite likely that you can get a better price than what you are going to pay for a RTW originating in the USA. Check out
http://www.informationlab.com/rtw.htm for example (this is a pricing chart for Star Alliance RTW tickets). The cheapest RTW starting and ending in Thailand is only $1606.38 (before all the taxes get heaped on).
Good luck! A RTW ticket is definitely adventurous and worth it...