I have been on an e-bender of sorts looking for touring answers, and shortly
after
finding this site and reading all the topics I think I found a fantastic answer
to mega
lightweight touring:

http://www.panniers.com/panniers/tailrider/overview.asp?fl=1&site=

Arkel makes this little expandable ditty that sits atop a rack and is perfect
for light
touring. I think this will go atop my seatpost rack nicely without ruining the
handling
characteristics of my bike.

I hope to go to Costa Rica in March while it is still dry and plan on taking
next to
nothing. Some wool shirts, flip-flops, and a Hennessey Hammock. Maybe even a
toothbrush all on my trusty steel lemond.

Anyone been to Central America?

Any shady stories about theft?