hmmm.... most of the brown ones I've seen were vintage, and thus a bit on the pricey side. Are you looking at motorcycle places? cause yeah, they are only going to have black, it's just an unwritten law of motorcycle gear. I'd start looking to the steampunk folks on Etsy and anything on Ebay, there is brown out there, I'm sure of it.
All that said, leather does paint... okay... but full color change is not something I'd recommend, and trying to go lighter from black, ugh, even harder. Now a light colored leather item can be polished with colored shoe polish to get darker tones, those often look fantastic, because you get depth of color and it doesn't hurt the leather at all.