I agree with MTS - I like OBW with limited colourways, too many colours come out too busy and not that different from the original fabric. 3 or 4 colours or colour groups would be a maximum for me. I think your fabric will be subtle and elegant but very striking and if there's not enough pizzazz for your taste when it's done, you can snazz it up with some applique, like I did here with my 'Orchidacious'. :-D
http://www.quiltingboard.com/t-92716-1.htm
I see you mention s n w or 4PP - I'm not sure each block would be striking enough to stand alone between sashing - I'd OBW. ;)