There are intakes available to run larger dellorto sha carbs, bing, phbg dellorto, and I believe even mikuni on polini speed cases.-I think this typically ends up cheaper than going with reed valve cases.
You can do all the mods with a hand drill and file, you could get some standard cases to practice on and keep the cost lower.
I would spend the time looking for a kickstart aftermarket case if you go that route. The Superbravos are pretty cool, kind of nice not to make changes. There will be some funny buisness getting a freewheel for pedal start to work too.