Once painted the Cinderella carriage can look quite good

(
source) though the wheels are a little... odd.
Warlord Games have an interesting
Pike & Shotte General's Coach (OOP? Doesn't seem to appear among the P&S products?)

outmoded for the 18th C. but with a removable top and interior detail.
Though the driver and shotgun rider look 'cartoony' the Alternative Armies
Londinium Coach deserves to be considered. Removable top:
