You don't need as much glucose as you think. For your 8-10 mile runs (anything less than 90 minutes, really) you don't have to take anything mid-run. You've got enough stored already. You can refuel after the run, and many people in the challenge have had success with mashed bananas and sweet potatoes.
As for the longer runs, I've had players make their own mid-run energy sources from dates that they have simmered and pureed, as well as the mashed banana and sweet potatoes I just mentioned. They just carry them in a small ziploc bag. They rip the corner off and squeeze right into their mouth.
I am attaching a few articles form Mark Sisson of Mark's Daily Apple. He is a former endurance racer and has some advice based on his experience for people who are doing what you are doing. Now he actually mentions making fuel sources out of molasses and honey as well, which you can't do on the challenge. But you may find some of the information about what an endurance racer needs to be interesting.