Staying with the G.M. brand of flours your best bet will be to use All Trumps which comes in at approximately 14.2% protein content. You won't find any flour containing more than about 15-ppm potassium bromate (if I remember correctly, 20-ppm is the legal limit for use).
As for the gluten, all vital wheat gluten is sort of a tan color, that's just the nature of the beast. I've never seen the use of added gluten turn the crumb of the finished bread to an off color when use at normal levels, typically between 3 and 10% based on the weight of the total flour. Keep in mind that each 1% vital wheat gluten that you add (based on the total flour weight) will increase the total protein content of the flour by 0.6%, so the addition of 2% VWG to All Trumps flour will give you roughly 15.4% protein content. Also, be sure to increase the dough absorption by an additional 2% for each percent vital wheat gluten added. As for dough conditioners, I am assuming that you mean dough strengtheners. There are numerous dough strengtheners available but you might have a problem accessing them as they are intended only for wholesale applications. In any case, you might contact Cain Food Industries, Dallas, Texas. They might still have their bromate tablets available, but if not, they have oxidative enzymes that are very effective at replacing bromate without the associated potential health issues of bromate.
By the way, the flour that you referenced contains 50 to 60-parts per million (PPM) potassium bromate. This is a level of bromate that has not been used in the U.S. since the late 1960's. The use of bromate has been banned just about world wide due to its potentially carcinogenic implications.
Tom Lehmann/The Dough Doctor