We have the lifter failure in our Ram Hemi's too. For us, the strategy appears to be: run Redline 5w-30 oil with high amounts of moly, then send used oil off to Blackstone for an analysis. They tell you how much life is left in the oil, and also the amounts of wear metals (iron/copper/aluminum etc) that is inside your oil so hopefully if your lifters are on the way out then that should show up in the report before it happens.
One theory why this is happening (to the hemi); high idle hours, cop cars etc sit their and idle and with that usage you need to change the oil every 2 to 4 weeks, which isn't going to happen with a cop car.
Second theory which might apply to your 5.3 as well since you have a similar lifter setup; dirty oil gets into the needle bearings and seizes them, preventing the lifter from rolling on the cam. Eventually the lifter takes out the cam, it just grinds the lobe flat over time. If this is the case, a very high quality oil filter from Royal Purple or Wix can help, as well as a high quality oil with good cleaning detergents in it, and of course change the oil on time.
So we are running a thicker oil, Redline 5w-30 is almost as thick as some other 5w-40's. But the hemi originally called for a 30 weight, previous manuals state 30 can be used when 20 is not available. This voids our warranty of course if they find out, since Redline does not meet the spec (or rather, they didn't pay to get their oil certified).
I don't know what I would run in your case, but I would definitely do the used oil analysis as well as lower oil change intervals for some peace of mind.