Ranger,
I am also interested in shooting from tripods. I recently read "The Ultimate Sniper" where several photos depict military snipers in the middle east. They recommend using sandbags hung from the tripod to add weight and stability. There are some tripods legs that ratchet down to the ground for low positions as well.
I would like to compare groups obtained with bench rest, prone on sandbags and with tripods. I know my purist bench rest friends think this is blasphemy, but they only want to punch paper for the smallest possible groups.