Checking on ITN, it appears that CO has flights to MAD with connections to BCN using Air Europa. It seems that there are currently lots of available seats for upgrades on some random flights I picked out--but remember you would have to pay the higher upgradeable fare at this time. If you book in April, you may be able to get a lower fare, but then have to pay a $300 or $400 fee on each ticket to upgrade.
Now to your odds of getting those seats....its a question of how many elites get in front of you for those upgradeable seats. Since in any event, you won't know if you've made the upgrade until 30 days or less before your flight.
PS-- if you are elite with any other carrier, you may get comped to a similar elite level by CO which could improve your chances on the upgrade list.