Planning an Epic Campaign

I'm not doing a whole lot of DMing at the moment, but I have some planning to do -- in a few months I'll be taking over the main group's game and trying to figure out what to do with a group of 7 very good players that will take them from level 21 to 26. That's right, Epic Level play.
I find the prospect pretty daunting. I mean, part of me looks at the idea of playing at that level and recoils, afraid that the players will just be impossbile to challenge. That part of my brain is clamoring for me to just run the PCs through some epic level print adventures, rather than trying to create the encounters myself.
But the other half of my brain is frustrated with the idea of not creating my own material. I mean, I might pull some crawls and delves out of print stuff here and there, but by and large I want the creative high I get from designing my own material. At the same time, that opens up a whole lot of other crap that comes with it -- stress over whether I'm challenging the party appropriately, am I giving everyone a chance to shine, do I have time enough to develop the game, and so on.
In the end, I'm coming down on the write my own side of the fence -- but it's more about the desire to be able to work Epic Destinies into the campaign in a significant way that really make the difference for me. I don't want destinies to be an after thought -- I'd rather they be something that is driving the campaign. The challenge there is that I need to have character destinies ahead of time . . . or do I. I'm going to have to make a pretty careful study of the Epic Destinies that are out there to choose from.
Any advice out there?