I’ll second Dwight’s note on Unique. And with you being in the Atlanta area, you owe it to yourself (and your wife…and maybe your father-in-law, too) to make a day trip over to Gadsden, AL to check out their facility. With originality sounding like it's high on their list, they will appreciate a Unique. It is also one of the few that has an independent rear (Jag type) as standard equipment. A plus for your wife in originality, and for you in tracking. And the Weavers at Unique will work with you to give you what you want.
A somewhat local (McDonough) 427 FE engine builder is Southern Automotive. Or, if you and your wife want more of a hand in building your own, and a possibly less expensive option, you could use a 390 FE block with one of Barry Robotnick’s (Survival Motorsports) stroker kits to give you 445 cubic inches. The 390 blocks are easier to come by than 427s, but the power potential for you to play with is still there, and they will look the same in the end.
While I seem to be leaning in the direction of originality to keep your wife and her father happy, the Unique with one of these engines can give you all the best of both worlds….and be close to home if you want to drop in and check on progress, and an easy trip when it is ready to pick up.
Here are some links to the above, and a couple of magazine articles featuring Unique.
Unique Motorcars
Southern Automotive
Survival Motorsports Home Page
Unique Motorcars Kit Car Shop - Featured Vehicles - Kit Car Magazine
What Makes Unique Motorcars So Exceptional - Kit Car Magazine