Everyone and thier old man knows Ducati's bevel twins legend, and the 916/Foggy era that made Ducati mainstream; the missing link is the aircooled rubber duck racers from a forgotten era. Tony Rutter took four (count 'em) world championships for Ducati on his TT2 racebike yet the roadgoing version, the 750F1, can still be bought for half the price of a bevel 900SS.
Cheaper still is the 350/400 F3. Same frame and bodywork, just needs upgraded brakes and suspension (the same as most 25 year old bikes, then) and a bigger motor. This lovely chap got to just £1900 on eBay despite loads of shiny stuff and a 650 Pantah engine having been added