Well first I only want a mild lower, not slammed totally, I dont like the looks of any tuck at all.
Second, I like flushness but just a little bit of sunken wont bother me to much. I would like maybe a little more flush then that F50 but I would be just find with that much sunken too.
I would rather have a meater tire then totally flush, with x8 +12 I dont think I could fit a 235/45 it without major problems, with the x9 +27 I dont think I could run a 245/40 on it and clear coil-overs and/or rolled fenders. The x9 +27 may hit coil-overs as it is.
Over all I think 17x8 +27 235/45 would be my best bet. It will be alot more flush then the ole' steelies and will look pretty good. And I should be able to fit a good tire on it without a roll even like you said, even if I have to roll thats no biggie.
According to Gram Lights site all 4 lug 17x7's have 36mm of lip, 17x8 62mm of lip, 17x9 74mm of lip. So if I'm reading that right changing the offset doesn't mean you get more lip.
http://www.gramlights.com/wheels/57pro/index.htm I'm pretty sure the number in (xx) means the amount of lip in mm. Correct me if I'm wrong.