There's nothing inherently different about the cage requirements between a sedan and a station wagon; in either case it's just a matter of applying the rules to the details of a specific design, not so much to the generalities of a body style.
I mean, if you're going to do something nuts like relocate the driver to the way-back, then yes, that would need to be taken into account. I don't recommend doing that without explicit permission from Lemons HQ before you start working on it, though, as there's a fair chance they'll say no, or at the very least they will have many, many questions for you.
1982 MG Metro 1300: IOE 2015 Pacific Northworst GP, Longest Distance 2010 Cd'L Box Wine Country Classic
1980 KV Mini 1: Worst of Show and Fright Pig Supremo 2009 Concours d'Lemons
1978 H Special: Second-Round Elimination 2010 Lemons Pinewood Derby at Sears Pointless
1967 SAAB 96: IOE 2012 Pacific Northworst GP, Organizer's Choice 2022 Hell on Wheels California Rally