Based on personal experience I would avoid saildrives if possible. They just don't seem to be built for durability. For instance, ZF will tell you that prop shaft seals
should be changed every 700 hours and the shafts themselves every 1400 hours. Clutches can go every 1200-2000 hours. The shafts and related parts
are very expensive and they will resist selling you them. They want to sell you the entire leg instead - think more that $4000. I suspect boat manufacturers are using them because they represent an easy and space saving way to install engines.
Having said this, beside ZF, Twin DIsc makes an SP60 for your probable engine
size as does Sillette (Sonic drives). Beta and Nanni engines (both using a Kubota block) use the SP60. The Sonic drive has been used on Gemini
cats for some time. They have the advantage of a traditional engine
mount and optional bronze lower unit construction. Good luck.