We saw a caravan like ours (Swift Speedbird 490, year 2000, fixed bed - based on the Dutch Toscane) where the owner had taken out both bench seats at the front and replaced them with cream leather stressless recliners and footstools (removable) and a coffee table which raised up to eating height, plus a cupboard to hide his battery compartment. All except the footstools were fixed to the floor, made from the same rather pale wood, and laminate as the original, and he'd replaced the flooring with a wood-effect expensive vinyl. It all looked rather nice!
We do lend our caravan to my sister and her family and they use the front beds though, so for many people it wouldn't be practical. However, I wouldn't have thought it was beyond the skill of a competent DIYer!
I wouldn't want an end bathroom - we've never used the shower in this one in eleven years, and in May had to remove the shower valve as it was leaking, due to frost damage. The replacement is £90.00 and it seems silly to spend that amount of money on something we don't use, so we've capped off the pipes and covered the hole with a wetwipe dispenser.