We have a Coachman 545VIP with the rear bedroom - brilliant idea - but the bed I'd not over long - I am about 5ft 10 ins and it's only just about long enough - would happily sacrifice a few ins off the bathroom for a longer bed - but that's way it goes.
Coachman are a quality van but are expensive and very heavy - I tow mine with a Volvo XC60 and it's perfect - but my Insignia Estate didn't like it at all - so worth bearing in mind.