My '05 ram is so high up and has more than enough tire clearance with factory 245 17 inch tires that I was wondering about what would be involved in lowering the chasis. Just wondering, it may cost too much or would not be practial. I was thinking it would help with mpg as a side benefit due to less wind resistance. Any thoughts appreciated.

The only way to get better gas milage is to trade it in on something smaller. It has the same front surface area going down the road unless you alter it by taking off some body parts.