Hi Nate.
My 2000 Dodge Dakota, 4cylinder cummins diesel gets 24 mpg. It is a 4wd, 4 real doors, crew cab, with less than 160K miles on it. My Cummins swap is well documented. It has a rebuilt 47RE with a brand new torque.
Sorry about the shakiness of this video; I was just learning how to take video with my iPad:
http://www.youtube.com/watch?v=WeWeJOXowOc
And I will echo what Tyler said, you definitely need to up your budget.
Oh, I just read your ad. My truck may not work for you. It's black. It is from north central Florida though and has NO rust.