You may be worried for nothing. I just measured the gap between the smallest cog's teeth and the dropout face on two Litespeed frames. One has a 10-speed Campy Chorus hub and cassette with an older Wippermann 6 mm wide 10-speed chain. The second has a Dura Ace hub, a 9-speed Shimano cassette and a 9-speed Shimano chain. In both cases the clearance is 3 mm or a bit less and the chains never rub on the dropout faces.

As DaveSSS mentioned, the clearances between the dropout faces and the front of the lockrings are much less. Less than 1.5 mm for the Campy hub and a tight 2 mm for the Shimano.