Yes...like Suzie says, the First Wheels City Twin (very wide and a bit rickety) and the Bugaboo Donkey (expensive)...then there's the Baby Elegance Beep Beep Twin, the iCandy Pear (but you can't see the child at the back unless you run round the pushchair), the Baby Jogger City Select (probably the best option for seeing the children and reclining them but its heavy to push when they get older), the O'Baby Zyngergi Zoom (not great quality and expensive once the warranty runs out to repair), the Kolcraft Contours (fantastic, great seating positions, bargain price, but fixed handle - good height, but large odd fold), The Bebecar Vector Duo, the Bebecar one & Two, the Mamas and Papas Duette, the Mamas and Papas Skate with Junior seat (simply awful), the Uppababy Vista with Rumble Seat, and the ABC Adventure buggy with toddler seat.
There's also things like the Babystyle Lux Twin, Emmaljunga Twin and a whole host of similar ones but they seem cute for babies but I wouldn't have thought there would be room for two toddlers - or at least not to poke and prod the other!?
Not all these have both children parent facing but most do. Most are on www.bestbuggy.co.uk if you want to compare statistics of any two side by side on screen.
There's probably some more as well....There are some others like the B-Dual do in theory work parent facing but in practice its not good (the car seat works well parent facing on the B-Dual).