You can change out the rear hubs to dually hubs and keep your same axle. Should be about 2" narrower than a dually rear which will help u tuck a little.
really now thats what I was asking amonth ago and know one would answer me if it brings the hubs in far enough that will save me $315.00
if I remember right its closer to 3" each side
Here are a couple of more pics of the progress i have made. If you would like to see some more pics you can also check out My Myspace page. Theres some other stuff i have built on there also.