Rosewood and other exotics will not necessarily be good for resale. As you say, keep it neutral. Maple or cherry are good choices. And you are correct, rosewood, ebony, and others will run you 500 or more just for material. Depending on how good the craftsmen is, the labor cost will be high. I've veneered many speakers in my day, to be done correctly is not an easy chore. Raw veneer will give a much better finished product than backed material, but is a lot more labor intensive.