Don't reject this for its simplicity:

Run twice a day, every single day. Start as small as you need to but make sure you repeat in the afternoon/evening what you did in the morning. Don't take days off.

As far as the categories you outlined for a discussion, the benefits of this are severalfold: 1. it's cheap... running shoes are generally replaced every 500 miles - compare this to a gym membership 2. You never hear anyone say, "I just finished a month's worth of 100 mile weeks and I can't seem to get in shape". 3. Avoiding rest days changes the low standards we've set for ourselves - if its been a given for the past six months that I will run today, then I can't rationalize my way out of it. 4. Though some are preferable, you don't need a specific venue or climate to do this. In the lower 48 states, there is no area where you can't do this all year 'round.

The downsides are mostly that it is tiring and rather unpleasant. You also might get injured. Listen to your body and that probably wont happen.