Personally we charge $5750 plus tax for a prebuilt uninstalled unit rated to 750whp. We charge $750 to install including fluid, hot flush, and adaptive reset/quick learn.
That's good clutches (18 friction C1, 7 friction C2, 6 friction C3/C4 w/LML springs and pistons, OEM C5), Goerend billet stator billet cover triple disk (R and any extreme clutch converter is an extra charge), deep pan kit, new filters, new bushings, new bearings, new pump, new wire harness, new speed sensor(s), new pressure manifold, new seals/gaskets etc, C3 oiling mod, hyd mods etc.
As for the driveshaft, a good driveshaft around here is ~$1000 for a 5" x 1/8" wall aluminum shaft with 1480 joints/slip yoke. The rear axle yoke can range from ~$150-$500 depending what yoke you decide to use, be it the dodge undamped style or gm damped style. Getting a driveshaft rebalanced and u-joints replaced around here is $200ish last I checked with Spicer lube for life joints.