first, your concept of spacers is a bit off as poised in this question. spacers will only hurt your fitment in terms of fender if you already have the desired fitting wheels.
second, your goals don't really intermesh. you want a flush wheel but you don't want to stretch. if the wheel is flush and you go bulging tires the tires will stick out past the fender. if the tire bulge is flush, then the wheel will be sunk. you can't have it both ways.
best option for you imo is a conservative 8" wide wheel. pm dapcwiz. he had rota grid 8+20s. not sure on tire size but car wasn't too low at the time, which helps mask sunken fitment, esp with a big tire. wasn't too aggressive and seems to have the balance you're looking for.
another buddy of mine threw on some 9+15s with 245R 225F for the hell of it. his car is needlessly 4x4ing, so its fairly relevant. looked like this.
rear 245
both 225F and 245R
as you can see, wheel is nominally flush in front and just a bit sunk in the rear... but 245 will not protect the wheel from curbage. if you went with a wider tire to fix that, the tire would stick way out. and it really looks like ass with the car so high. in other words, i think you'd be best going with the option above... an 8" wide wheel with a conservative offset and a fairly fat tire.