How far down do you want to go? The front spindles are the same either way.

If you really want to ditch the 4x4:
Trade the 4x4 trans and transfer case for a 2wd trans
Get a 2wd rear driveshaft
Remove the front driveshaft
Remove the front diff
Remove the front half shafts.
For the front wheel bearings/hubs you have 2 options, 1. replace them with 2wd hubs from a 2wd Tahoe, or take the ends off your halfshafts and insert them into the existing hubs. You can NOT run the 4x4 hubs without the shaft ends in them. They will fail almost immediately.

Since you have selectable 4x4, you can also just remove the front driveshaft, deal with the front and leave the transfer case in there. Just seal off the hole for the driveshaft in the transfer case and leave it in 2HI and remove the controller switch.

No matter what you do, you are still going to have to deal with the torsion bar suspension when lowering, so you may not gain that much by losing the 4x4.