Scour the jy for something with a 2 barrel carb. The Weber 32/36 is popular,and when I worked in the VW biz, we were also the biggest Weber distributor in the Midwest.Sold them for everything. Course you'll probly need to rebuild it , hard to imaging a 25+ year old carburetor working perfectly. You're adapter idea is spot-on, except i would do aluminum before steel for heat dissipation.

89 SWB, V-6 5SPD, OME Shocks, 16.5X37's, 2"BL, SR axle, Gen2 brakes, Lincoln w/Superwinch