+1 for going 100% wheat DME, which, as mentioned previously, is really more like 60/40 wheat/pils. I don't think you should need steeping grains. Not that you should negate them just because I said so, but the character of that style (and really any German wheat) comes almost completely from yeast (and in this case bacteria). Also, for increased head retention, you could skip kettle finings (Irish Moss, Whirlfloc, etc.) since cloudiness isn't a real concern with this style.