I've only ever added it to a stout, but you might try "dry-hopping" with some coarsely ground coffee beans...I have no idea how much color it will give the beer since I did it with a stout, but it will definitely give you roast flavor and aroma.
Thanks. Interesting idea, that. My goal is to have as light a beer as possible, but with flavors reminiscent of a nut brown. I think I'm getting there, but the hint of roast is what has me stumped. In the end, it won't be a nut brown, but it will be a fun experiment. My grist and planned flavor additions should throw the drinker for a loop.