One piece driveshaft swap

[trkfrmr]

I am thinking of replacing the two piece driveshaft in my th400 Dana 60 leaf axle equipped 67 c20,had new rear half made and need to replace center support bearing after 3000 miles.I measured the one piece in my 2002 lwb Siverado,it is about an inch too long.Anyone know of an application that would work better?I know slip yoke would have to be changed as well as trailing arm crossmember removed.Truck has had a vibration ever since build,not from wheels/tires.Most driveshaft companies will not build one as long as I need.Thanks