Sometimes you can contact a travel agency who will still have bibs even after they officially sell out! Check the list of travel agencies on the run Disney website!
You could also research running for charity. This will mean there will be a fundraising commitment from you, but perhaps you can find a cause you believe in strongly which would make it a win-win for you.
This is fabulous, I had no idea! Thank you so very much!!!
I just registered under a charity that is not only one of our clients where I work (CPA firm specializing in nonprofits) but also near and dear to my heart. Now I get to not only run, but raise money too!!!