I've used Brad Penn Penngrade1 30wt Break-In Oil with good results, switching to 10W30 after break-in.
And yes, as you know, there are lots of 10W30 break in oils available. A quick search at Summit brings up 10W30 break-in oils by Comp Cams, Royal Purple, Driven, Lunati and so on - but I've never tried them.
I have used Red Line Oil's Break-in additive in a more modern engine that I intended to run Red Line Oil products after break-in, and that worked well, also.
