#1 - Find a new dealer, you should be able to find one who will bend over backwards for you, let alone bring in a slide.
#2 - I can't tell you how many MH's I have driven, but I can't recall one where I was limited other than a few drawers. There was one so packed full of junk that you couldn't walk in it, but that wasn't the manufacturers fault, the person was a slob and used it as a storage unit. If they had a storage unit I wonder if they would have made that payment.
#3 - Don't let anyone tell you that you cannot drive with the slide out, I promise you can do it, at least once anyway.
Disclaimer - #1 is a serious statement. #2 is made based on the fact that I have driven 50+ MH's ranging from class B to 40+ foot pushers, some in a mad dash because the person who's driveway it was in thought they owned it, but they didn't realize the bank really owns it and possesion is the law when I am behind the wheel(have you ever seen a Diesel pusher fishtail? I felt it a few nights ago, and even with 2 bathrooms in that monster I didn't think I would make it). #3 is a joke and intended to make people laugh, we all need to do that once in a while. I cannot tell you what once in a while is, since I am not a doctor, but I believe I flipped one off on the expressway today.
Disclaimer X2 - The disclaimer mentioned above is true, although #3 is serious, and the last part of #2, that thing got away from me. Let me add that I have been drinking.