Yes, there is. I believe they call this method of taking miles out of OP "redeeming your miles for flights on CO or partner airlines".
Considering that UA Starnet blocks (and if the DL/NW merger's a guide, this means CO and UA accounts will get the worst features of BOTH programs), this probably isn't a bad idea. I know I had the option of leaving some CO miles around to become UA miles, and I chose cashing them in for a C/J intra-Asia trip on SQ and TG. I know that if God forbid, AS ever announces a merger with DL, I'll certainly cash out my AS miles before they become worthless SkyPesos™.
Generally speaking, airline miles are like the Hotel California. Airlines don't WANT you to be able to trade them for anything else without totally taking a bath in value. For instance, there's points.com GPX trading, but you'd be trading increments of 30K miles for whatever program you're trading CO to, at $300 a pop (so a cent a mile), and some of the trades just suck (people will post that they will give you 10K AA miles for your 30K CO miles). Not worth it, IMO, unless you're desperate for some topoff figure of AA miles or something. I've also seen horrendously bad cashouts on points.com as well- I recall an offer where I could trade a figure of US miles close to a North Asia F redemption (so nearly 120,000 US miles) for a $100-150 Starbucks/Amazon.com/Marriott gift card.
Hmm, tell you what, points.com, how about I trade those miles for a first-class trip to Hong Kong with a stopover in Europe instead. Thanks for the generous offer, though!
There's also the possibility of using them for hotels that CO just announced, but it appears that that's also at 1 cent per mile, which is a pretty terrible redemption rate (and I looked around at prices for hotels
that site was offering, and they weren't so great- better off using cash and whatever combination of hotel aggregation site/Priceline/Hotwire offers good value).