This link has been posted in the past by Machka:
http://www.ultracycling.com/nutritio...iders_eat.html
In summary, the vast majority of calories consumed by RAAM riders is "Ensure Plus".
Pick up a can of it and you see the principle ingredient is maltodextrin.
I have posted this before:
http://outside.away.com/outside/body...hydration.html
You can buy the Jeukendrup mix commercially as "Powerbar Endurance".
Another poster just posted that REI has it on sale for $11 for a 2 lb can:
http://www.rei.com/product/714914
I've been mixing my own for the past couple years, for ~$3/lb (including shipping costs).