I'll chime in.
Having been married not too long ago, I can relate. I also looked for a classic car to go on the wedding day (especially to take the bride from church to the reception), so I can both understand the desire and the persistence, as things that one trully wishes you have to fight for them.
I can also relate to the budget indications - we did a small wedding, and still ended up spending a lot of money - but WAAAAAAY less than ordinary. However, foul as it may go one day, the fact remains that YOUR wedding day should go as you plan it, as it will be your day, not anyone else's. That having said, boy, 450 family and friends... w00t... and you'll still pay for accomodation? Wouldn't they come to your wedding anyway?
As far as the car goes - we endend up being lucky by not finding the classic (was looking at an AC Cobra, which was the only classic car I could find locally), as on the wedding day it rained cats and dogs throughout. Still, it would have been awesome.
So, after all this chat... what I wanted to say is that Kenny is OBVIOUSLY not trying to scam anyone, he started doing this a long time ago, and is genuinely trying to find something to fulfil their dream.
Won't anyone try to help him? Maybe arrange a day to meet both, and see how they are, and how you'd feel with him behind the wheel? Maybe see if he adapts well to the stick-shift, and if she believes she can enter the speedy with the big dress...
I do think that, not being friends, one does the right thing by reaching an understanding on a compensation for the car usage, but it doesn't seem likely that he'll trash the car with the bride in it.
Plus, going to the wedding you can keep tabs on everything that happens - and you may just have a nice time as well.
my 2cents.
P.S.- Why so hard-strong on a color? While it will help emphasize the white dress, sometimes the interior combination (ie, red) could be a bit sporty for weddings, imho. I'd keep an open mind.
Plus, Gabriel's ivory... what a gem!