I love the pavers! What a great idea! This past summer I, also, built a 10 x 10' keyhole raised bed and I love it! I scrounged the neighbors and found several large logs, rocks and bricks. I cut the logs to fit then filled in the short spaces with large rocks (the logs weren't quite 10' long). I used the bricks for a mow strip. Yes, a couple places needed a good stretch to reach but I solved the problem with a 2 x 10 that I rested across the bed and used as a kneeler.
I know the logs wont last forever but by the time they need replacing I'll have the time, money and plans to make something more permanent. I hope! I'm in my late 60's so I might not need to do anything. LOL
Here's a pic just before I laid down the mulch.