Stuart,
I admire your vision, tenacity and perseverance on trying to revive the Cougar. It has always been an interesting and efficient part of the light twin round-up. Having a similar interest in this arena, I thought I'd throw my $.02 in here... for better or worse.
Over the past several decades, I've tried to get response concerning the viability of overhauling, resurrecting, modifying, maintaining, and just supplying parts and service to Beech 95 Travel Airs. Airframe prices fluctuate depending on the price of fuel, the availability of good Baron equipment, and what recent AD Continental has issued on their engines. What I've unfortunately discovered (for the most part), is that few want to spend any money on resurrecting these old semi-entry level piston twins. They have no problem dropping $150K on a Baron [even with no deice], and putting another $100K in it without blinking. When you start talking about what many consider as 'training' aircraft... Travel Airs, Twin Comanches, Apaches, Cougars, and to some degree even 310's, people are no longer willing to spend money on them anymore. They will use them up, and dump them like a worn-out commuter car before they'll start restoring them to any significant degree. We've all seen them all over the country languishing in the back of a hangar or out on a tiedown at the far reaches of an airport ramp... sans many significant components required for future flight. 'You'll have w-a-y more in it than you'd be able to sell it for', is the common refrain. Which is correct. For the most part, many have become disposable... but in the not too distant future when the reality of 'there ain't no mo' hits, I believe we will all regret this tact. That day may be closer than you think.
I was going to come out with some mods to make life much easier for Model 95 owners, and save them a great deal of money and hassle in the long run (@ great expense to me personally), and couldn't even get any amount of enthusiasm or semi-commitments for that. People would just rather nurse them along illegally rather than spend a reasonable amount of money to get things correct and save themselves future hassles and problems.
It is an uphill battle these days with the entry level piston twins. So many people have already commented on here with great insight and sage advice. There is a market for certain "cheerleaders" and support people for these older types. In fact, I truly believe that's what will stand between them making it just 10 more years, versus another 20 or 30. My personal objectives in this regard have been paralyzed for the time being due to several factors, not the least of which is the crash of the stock market over the past year. The "Labor of Love" money is just not there now for the time being.
You may have to take this on as a 'labor of love', rather than a grand manufacturing project for new airframes. As many have said, and I sincerely hate to admit, the market is just not there at this time... particularly when there are still numerous options in the used market to choose from with greater support. Also, your $750K figure might be a tad optimistic for a new-build airframe, unless you already have access to certain things that we don't know about. A Cougar is a much simpler airframe than a Travel Air, but that price was about the same as what a restored basic Travel Air would come out with, not a completely new build airframe. That's why new equipped Model 58 Barons are scratching through the $2M ceiling now... and that's with the benefit of a large and respected manufacturing, marketing, service and reputation base.
Best wishes in whatever endeavor you attempt, just remove the 'rose-colored glasses' and take a long hard look before you begin throwing copious amounts of hard-earned cash at it. Don't let the love for the airframe blind you to reality... unless of course, you're the recent winner of the $1.6B Powerball jackpot. Go visit Vegas instead.
~
ME 