Do a whois lookup on the .com and you'll notice that one is for sale too. If someone really wanted such a name then unfortunately they'd probably go after the .com first. Thankfully, you can get the email of the .com owner doing that same lookup and you could probably contact them to see if there is any interest. If the .COM gets type in traffic they may lose a bit to the .CO and since it's so similar, you might be able to get a quick/cheap sale to that owner.
Honestly, I don't see this name having much value undeveloped. If you could contact that owner and flip it for mid-$XX to low-$XXX I'd do it. The new owner may have interest since he could package the two for any .COM potential buyers. Once again though, he's obviously a domainer so he would be paying reseller prices, not end user prices.