OK I have made them. They were not particularly hard just take a little bit of time. If I was going to do this again I would probably make the mini pies and the frosting a day ahead of time to avoid a full marathon baking session. The cream cheese cake batter creates a denser cake than your average white cake recipe (or mix for that matter). I SUSPECT that you could probably still make everything work if you used a different cake, but I would use the more skookum foil lined baking cups instead of the flimsy paper ones and be especially careful to let the cupcakes cool completely before trying to handle them.
I was also unable to find cinnamon chips so I made butterscotch chip ganache and added cinnamon to it. I did not end up adding the entire ganache because I felt that it would become TOO sweet. This is by far and away my most favorite frosting recipe of all time now and I look forward to tweaking it for other uses. I made it in the stand mixer so it got really fluffy and is to die for.
ProTip - Get an extra pie crust. You'll have enough pie filling left over for a couple pot pie sized pies or maybe a smallish regular pie.
Second ProTip - I also ended up with enough batter for 6 more full cupcakes but had only made 24 mini-pies. You might also make another dozen mini-pies and probably get another 6-8 cupcake combos.
Hey are you guys with the Un-Americans? haha, just kidding. I have no problem with the USPS sponsoring Lance Armstrong. I doubt this is the first time they sponsored an event like this so I won't criticize their rate hike.