Just a follow-up to let anyone interested know that the lifter noise was indeed caused by low oil pressure due to failing oil seals. Seals were replaced, and all lifter noise and rattle on cold start are totally gone.

I *still* think oil seal failure is unacceptable in a correctly maintained engine with only 60K, but I guess that's just my opinion.

On a side note: although the oil pump (and hence the seals) were replaced under warranty at 49K, it turns out that the usual 1 year/12K repair warranty does *not* apply to repairs performed under original warranty. Warranty repairs are only guaranteed until the term of the original warranty expires. In disbelief, I checked this policy with VCNA, and then with BMW, Mercedes, and VW. Same apologetic answer everywhere. I got a 15% discount on labor via my (also apologetic) sales rep but wound up footing the rest of the bill myself.