There is no need for the air cab. The air cab is most useful when you are running light and the road is rough. Once you build your motorhome and load it up, you wont need the air cab to calm the road down. If you lock up the cab and then bolt the motorhome box to the cab, you have a solid unit and no chance for trouble inbetween the cab and box where the boot is.
The only guys I know that are blowing the top off a day cab into the overhang is Haulmark. But the crazy thing is they leave the airride on the cab. I think that leaves a lot of chance for water trouble with the roof of the cab being open.
A month ago or so a couple of different Haulmark employees went into the link section and added a new link to their new website. The funny thing is that they all put in a bogus URL.
Here is a link a buddy of mine sent me on a Kingsley walk through tour. (Only click this link if you have high speed internet connection)
http://www.bigeasy.tv/kingsley.html