My last horse took the provincial championship in road hack in a black saddle. It is not the 'in' color but I really doubt you'll be penalized because of it. I think as long as you have a well presented clean turnout (match your bridle to your saddle) you'll be fine. Especially at the local level.
I have a black saddle. I didn't mean to buy a black one, but I found this one used (but pretty much brand new). It's a very expensive big name brand which was a custom order but never picked up. Well, whoever ordered it must be my twin and her horse must be my horse's twin because you couldn't ask for a better fit for either of us. And I got it for a steal! Who cares about the color- how much of a saddle really shows while you're in the ring anyway!
"Life is too short to be a slave to the whims of others." -- RugBug, COTH