The answer was YES!

Matthew and Annie are engaged.
I got word at 4:30 Friday afternoon, when a text message popped in from Matthew.
It read:

You were right. She didn't let me finish. She said yes!

Matthew and Annie had been planning a trip in August for some time. Originally, the plan was to spend some time at a borrowed condo in Florida, but that friend's condo may have been the only piece of property in that state to sell. So they ended up in Petoskey, and they were on Mackinac Island when Matthew proposed.
Here's how Annie described it on her MySpace blog:

It was so romantic. We went for a hike to Arch Rock, such a beautiful site. He asked me there. I don't think I even let him finish what he was going to say before I said YES! My ring is still at home. He said we can go get it together to make sure it's perfect. He got me one while we were on the island in the meantime, but he said this one isn't for long. I love the one I got on the island. It's so pretty, too. I'd be happy with this one. We had a blast on the island, got those old-time photos taken, fudge, and ENGAGED! How could life be any better?

It's just the two of them Up North, which is the way it should be. Lexie, Annie's daughter is with us. She's snuggled up on my lap as I write this (one-handed typing is not my strong suit), and having a toddler cuddle close is just something magic.
Things are very tentative. At last word, the ceremony is likely to take place in 2009, after Annie gets her business degree from Grand Valley. Following that, the plan, I think, is for Matthew to adopt Lexie formally.
So am I a grandfather yet? Hey, I got the job, even if it might take a while for the paperwork to catch up.