more legroom! cab floor mod?

[cstanley]

anyone know if it would work very well, for the purposes of increased legroom, to make mods to the cab floor? i'd prefer not to go the stretched cab or door way, but more along the lines maintaining stock look. could the cab floor be stretched down or forward a few inches without getting into a ton of firewall issues? at least in the foot-feet area? maybe drop the pan on either side of the trans a few inches, from the fron of the seat forward.
what does this do to cab supports, etc?
thanks
-colin