Well it's from Early Times Distillery and not Makers Mark, but a barrel none the less. This is what I do with them. I just got an order for 15 more of them.
The Elevator Brewing Co. ages their Horny Goat Porter in them and then I turn them into their store displays. You could use them to age beer in if they've been stored properly, which they probably weren't. You gonna get flavors from everything that was stored in that barrel including the last beer. When I cut into them it smells like heaven! Occasionally they are pretty moldy though. The staves are about 1" thick and the bourbon can be soaked in about 1/2"!