"all it needs is Curb Appeal!"
What Rob Said!
Now, I do know of a local cruiser/retiree that has rebuilt a Valiant 40 and a couple of Cascade 36's. While he is converting his time (and doing it at his own pace) into eventual sweat equity dollars, I do not believe that he "pays" himself very much per hour...
He specializes in strongly-built hulls with a loyal (almost cult-like following) offshore voyaging clientele.
I could see doing this with a larger boat, and would put Ericsons and Tartans, and others of that quality on the short list.
The thing about boats under 27 to 30 feet (arbitrary line, admittedly) is that there are so many on the market that it almost always going to be cheaper to find one in a sail-able condition and just go out and use it.
The arguement for restoring a small Ericson would be that the basic boat construcion is solid enough to justify the personal time (days, weeks, etc) that would be required. To look at it another way, if you put the same amount of time into rerigging, a new interior, and a "full Monty" exterior LPU job on an old 23 foot Venture, you still have a weak lay-up hull and deck, subject to constant cracking and flexing.
Somewhat like fixing up an old house, first you have see if that house has "good bones."
Of course, that rebuilt and flipped house will very likely go up exponentially in value... not so likely for most boats... Well, maybe a Swan or Hinkley... maybe.
As to a boatyard.. well, I did exchange several emails with a yard on the east coast that bought s sunk Olson 34 hull after one of those big Florida hurricanes. They indicated that, over time, they were going to source a new keel, rig, and rebuild the rest of the boat. As popular and scarce as Olson 34's seem to be, this might be, IMHO, a break-even project. I dearly hope that they bring this hull back to life, though. And as long as they make a little net profit downstream, it should keep their workers busy between regular short-turnaround jobs.
Best,
Loren
ps: re-read what Rob said about a clean title. Lots of smaller boats have a zillion unknown prior owners and zero proof of ownership -- a few are still warm to the touch.