I also have a couple of active dogs (the Setter/Blue Heeler mix especially) and am gone a lot for work (also 12-15 hours a day). What works for me is putting them in a large dog lot during the day when I am not home, and bringing them in when I am home so we can play, etc. They have all day to play together and run around in the pen, and they still love to play with me, since it is then a special treat to get to spend time with the 'pack leader', (which authority I established when they were very young by methods described in most positive-reinforcement training books, etc). This is very important to the way my dogs relate to me. If I don't have them thinking I'm the boss, they would never be obedient or trainable.

When it's bad weather, they get to stay in the house alone, and are not usually destructive, since they haven't gotten too pent up. Unfortunately, if we have a week of bad weather or something, by the 4th or 5th day, we may have some minor destruction (pillow stuffing on the floor, etc). I just try to keep anything valuable away from them if I know they're starting to get pent up and bored.

Good luck with yours