OK... so a Dana 30 has weak unit bearings... BIG DEAL! If this guy wants to do a Dana 30 swap and has it in his mind to do it, why not give him the information needed to do it properly and safe.
Dude, If you are gonna do a Dana 30 swap, the unit bearings will last some time.... unless you are running too large a tire. If you want to run larger tires, there is a company that make some real nice stuff that should last a life time.
http://www.solidaxle.com/ProductCart/pc/viewPrd.asp?idcategory=17&idproduct=83
For what it's worth, I like the way you are thinking out side the box. Keep it up and do post some pics when your done. I wanna see them.. and I'm sure others do too!