I too am on my second Roomster and am hoping to get another 2-3 years from it before needing to replace. However there has not been an obvious successor as others have said. Recently I was given a VW Golf SV as a hire car for a couple of weeks in Germany and that seems the best alternative I have seen and driven, I was at least as comfortable as both driver and passenger as it has good headroom and two height adjustable front seats, rear seat space is good and the boot is larger than the Roomster, all while only about 90mm longer. Certainly significantly more compact than a Touran and much smaller than a Caddy / Tourneo Connect or Berlingo / Partner style vehicle. All of these are van based unlike the Roomster, whereas the SV is a car.