CO offers a Onepass domestic award for travel in the USA for a round-trip upgrade for 20K miles. I don't know if they have a one-way version of the award, but if so, it would probably be 10K miles. I think the awards (at least in many cases) are good for regular published fares. What is a bulk fare? The bulk fare might not officially be upgradable. Also CO offers upgrades where you can pay (based on the number of miles) to upgrade. Again, not sure this is technically ok for a bulk fare, but worth asking at the airport.