Dave, you probably don't want to cantaliever the deck just over the skimmer (the neighbors would talk... ) it wouldn't look 'right'. We always used 2' X 1' 'AQ' (if memory is correct?) cast coping on our pools. We would put a 8"x 2' x 1/4" strip of steel across the opening for support (and plan the coping layout so that 1 peice would span it - the steel was just insurance). Sounds like your idea of using a sheet of SS would do what you want (as I understand your last post, it can be inbedded in the coping morter, with space to spare. - you might want to paint it (i'm assuming again) white, with Rustolium or equivalent). If you want to tile it, go ahead, it's your pool and you can do whatever you want to it! If you tile the top of the skimmer mouth, you might want to think about using a different tile, it's hard to get 'top tile' to look right and using a complementary, but slightly different, pattern will lessen the effect. (Just my $.02).
I'm gonna go look at your other post to see if I have any ideas. - Happy swimming!