We have been down to comparing the 4100 to the 415 and finally got to walk through the 4100 this past Saturday. While the bathroom is awesome in the 4100, we didn't feel that the living/kitchen area worked for us and we decided that the 415 was the way we would go. I'm in negotiations now to purchase our first 5th wheel toy hauler!
My guess is that you can get 2 awnings on the 415. If the factory doesn't have it as an option, the dealership certainly could. I've found that after some research on this forum that there seems to be an unpublished list of options that doesn't show so you may want to reach out to the regional sales manager.
I'll also post this part elsewhere as I've been interested in a 6 point auto leveling system, which is an factory option and an aftermarket option as well. I was just provided a counter thought on that by the dealer... he would install the aftermarket kit, but the experience that they shared with me was that it usually lifted the rear up so high that the angle of the ramp was too steep for some toys to overcome.
Good luck,
Patrick