My 5yr old 60# girl has no problem being in the house 12+ hours when I'm working overtime. As long as she gets play time and exercise regularly she seems content. She sleeps all day even if we're home and is generally more active in the evening.
I adopted a 1.5yr old male 2 months ago and while he hasn't had to experience regular long work hours yet he did fine being crated for a couple 10hr days. He definately needed some play time to burn off energy those days but I planned on spending time with them when I got home.