if you need even bigger than that, early 60's vintage Mercedes 220's, and 230's came with (dual) 36mm 1 bbl solex's, and Land Rover 2.25 liters came with 38, and even 40 mm 1 bbl solex's.
are you just interested in added flow, or looking for a specific bolt on? ( some of the MB, and Land Rover carbs are turned 90* on the mounting when compared to the VW versions)
oh - and just in case its of interest to you, the very early Land Rover Solex 1bbls didnt use chokes - they use an idle enrichment circuit in its place **the improved airflow resulting from the lack of a choke plate actually gives them more flow than the later, 38mm carbs, while keeping the better low throttle control of the smaller venturi.(apologies if this has all been talked to death previously)
91 Niva 'Cossack', MB 240D, 4 speed auto, ~88:1 low, 30x9's, coil sprung, 830 RTI.