It's really unfortunate, but Delta doesn't provide this type of "cash & miles" ticketing option.

Strangely enough, this was something that NW had as part of its PerkChoice program. I remember over two years ago using 12,500 miles + some cash to purchase several tickets. A very flexible and convenient option, all done online.

But we've regressed to the stone age with Delta when they chose not to take NW's website and technology, so that option is no more. Maybe someday Delta will be able to offer something similar...