LOTS OF GOOD ONES!"Terific service" ACE [tennis serves are called "service"]
"Gross income source?" PORN
"Dash indicator" OILGAUGE [I was thinking punctuation]
"Conductor whose name is spelled with two musical syllables" SOLTI
"Man of steel?" BESSEMER [the Bessimer process]
"It can make a racket" CATGUT [some tennis strings are so made; most are man-made]
"Where sleeping dogs lie?" FOOTREST [
dogs is slang for
feet]
"Boxer, e.g.: Abbr." SEN [Sen. Barbara Boxer]
"It's a wrap" SARI
Very clever theme: the answer describes the letter clue as it is used in the answer. I particularly liked FOREGONECONCLUSION for "E" and GRANDFINALE for "D." The only problem is that MALCOMINTHEMIDDLE is not a common expression as are all the others; it's a title. But still, it is most familiar.
What is rapa nui?