What rear end are you running?? If its an 8 3/4 it may a better move in the long run, to get aftermarket axles for about $350 than to spend $100+ getting stock axles modified, particularly if your putting any power to the ground. (change to "green bearings" while your at it) Aftermarket axles can be ordered with dual bolt patterns so if you want to upgrade to the larger bolt pattern later, you can just move the studs to a different set of holes.

There should be no problem with the 1/2" studs and shank style lugs. I don't know about stock style steel wheels, but it should be possible with proper conical style lug nuts.

If you have a 8-1/4 or 7-1/4 rear end, upgrading to 1/2 studs may not be very helpful, as the studs are not likely the weak point in the setup.