Re: Optimal propulsion system
What you're proposing is gaining traction these days.. there are a few boats offering this kind of package, and you're right, it's not going to be inexpensive. Overall I think the electric drive will be best suited to the in-harbour/out of harbour needs of the daysailer, once you get into generators to power the electric power most of the advantages are lost. Getting enough solar to power up such a system will have its own challenges as well.
Good luck, btw, coming up with a powerful enough generator that no one else will notice running....
Emerging battery technology may well make this more feasible in the near future.. It's a neat idea...
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)