I would say get yourself the DJM arms, a good air mgmnt kit with 8 valves, then you will need some cups for the front, in the rear you will need at least a 6 inch notch as mentioned and if you really want it to lay your gonna have to relocate the fuel tank in the bed or get a fuel cell. Youe also gonna have to decide on a 2 link 4 link or 6 link for rear suspension. Your going to have to notch the gas tank crossmember and possibly the cab floor for the huge ass drive shaft, or possibly get a smaller shaft made.
So all in all your could looking at 2 to 3 grand in parts depending on what all you buy and what all you can fabrictate.
minitruckin the one of the best things in the world but it doesn't come cheap. i have about 2 grand in suspension parts for my daily driver. but like james said, do it right the first time and you will spend less in the long run.