Your length constraint pretty much means you're topped out in the 7 cubic foot class, but if the table at that thread I referenced is any indicator, you might be able to find a model that will actually hold four kegs without a collar. Maybe see if there was a follow-on model like the Kenmore 7.2 cf referenced here...
https://www.homebrewtalk.com/forum/...-specs-and-layouts.377518/page-3#post-4906444
Cheers!
https://www.homebrewtalk.com/forum/...-specs-and-layouts.377518/page-3#post-4906444
Cheers!