Hi, Eliška,
A cool question, really, often people ask about the longest but they don't think about the width that is really as, or more important, especially with a footmuff.
About wider than 33cm strollers - the first that came to mind is the Bugaboo Fox 3 with a 35cm wide seat unit. Even if the manufacturer says the ABC Design Salsa 4 (I know, foam wheels, but they offer the Air version too, and the wheels are really nice quality even foam-covered) has a 31cm wide seat, it is actually one large seat (I believe they were measuring in the back) so I would actually suggest thinking about this one as well.
The Inglesina Aptica, and also the Uppababy Vista or Uppababy Cruz also have a 33cm seat, and the reversible Gesslein seats are 34 cm in width.