I've ridden centuries on plain steel road bikes (a looong time ago)... or are you just more concerned about your injury and it's impact on what you think you can ride?
Have you considered some home PT for this? I have read that some think rolling is great for ITB problems - I used rolling on my calves for a few weeks with terrific results, both for plantar tendon pain and for calf pain. Different problem, but great affect. And you don't need much equipment. I just used a piece of PVC pipe.http://nyvelocity.com/content/coachingfitness/2010/proper-technique-rolling-your-itb
I'd like to be able to ride some centuries.