I got my elec inboard from thunderstruck-ev.com
It was $6k ish, Inc mounting & gearing assembly.
They're awesome folks, I even got the kit open, realized I was in over my head
, called em and they agreed to take it back, wire all the individual bits together and label the rest in a "for dummy's" manner, and send it back.
Cannot reccomend high enough, 287 out of 5 stars.
As far as the sail drive issue, if the lower is bum - drop it, glass the hole up, install a cutlass bearing/prop shaft and you're good to go.
Or go w a Honda
Or torqueedo, I've heard of a 33' Benny bopping around the Caribbean
with a 10hp one quite happily. Dunno how that works, but that's what I've heard. It's a hell of a lot easier to mock up an outboard bracket than a direct drive or sail drive, after all. Plus, elec outboards won't get swamped, so you get rid of a ton of the issues ICE outboards have (apply extra silicone lol)