Your best bet would be one of the old OMC sail drive units. It basically is a 30 HP outboard turned into a 15 hp sail drive. There was a company adapting Honda outboard engines to sail drives a short time ago, but I haven't looked for a while (Saildrive 280). SAILDRIVE.INFO - Selection
Try this site lots of useful info. I have no connection other than a google search. In my experience, it is rarely less expensive to engineer a new system. That is hanging an outboard on a boat that originally came with an inboard is easy. Converting a boat that came with an outboard to an inboard, not so much. Converting an outboard to saildrive, and cutting a 2x3 foot hole in the bottom of your boat to mount it, well it could easily be the long way around.
does anyone have any information about converting an outboard for inboard use? the cal27 i just bought used to have a vire 7. it is gone and the previous owner mounted a bracket on the transom for an outboard ( which is also not there, now ). i would rather have inboard power thasn outboard. i personally don't care if it is 2 stroke or not. if there is a 4 stroke option i would rather that.
i am working on a....restrained budget. so, if i could find a way to convert someone's old outboard to inboard use, that might be just wat the dr ordered. sorry. not trying to hijack the thread or anything.