Are there any body fat/BMI/metabolic rate calculators (online or software) that have an option for choosing your ethnic background?

dont think ethnic backgrounds really effect anything..genetics on the other hand is different.

Actually, some factors such as bone density can vary by race. Age can also be a factor as bone density tends to decrease as you get older.

I've never seen anything that takes these variables into account but I'm not sure that it makes much difference. Any method that you use is only an estimate anyway. The absolute value of your bf% is not all that important. You're really concerned about the change in bf% over time.