I grew up riding horses and motorcycles. I really prefer a full flap design for such activities, it keeps dust, dirt, and weather from the gun.
I'm also an adamant leather fan, a good tight fit keeps the bluing ware to a minimum, and a quality holster is far more comfortable, and durable.
The elpaso saddlery link above has some excellent styles, another top-notch site is yodercustomleather.com, there are surley a few more out there, these are just a couple.
I have always been curious as to what everyone else chooses for carry, how well it all works, and the personal preferences chosen and why, good topic of conversation IMHO.