Hi, guys. First post. Anyway, I've actually found a really easy method to make your inserts wrap. I'm pretty sure I'm the first one to do this, but if someone else has posted this, I'm sorry. ^_^;; As a note, it's not exactly genius or anything, but I hope it's of help to someone. >.>
OK, you need several things, really. First, you need to know the dimensions of the inside of your pen (Mine goes 3.5 in length, 1.5 in circumference, but yours may be different). And secondl, you need a design.
1. Start a new image, with the width being your pen's length and the height being 1/2 of your pen's circumference.
2. Design your image, whatever you want it to be. Copy it to your clipboard (CTRL + C).
3. Start another new image, with the width being your pen's length and the height being your pen's circumference, and paste your previous design onto this one, twice, one on top of another.
4. Select one of the halves of this new image, and then flip it vertically. Copy this design onto your clipboard (CTRL + C).
5. Make another new image, with the width being your pen's length and the height being 2x your pen's circumference, paste your previous design twice, one on top of another.
And there you have it, your very own wrapping design. Here's a result I got after cutting up one of the inserts in this thread:

Here's a little blurb about why this works... If you're not interested, don't read; it's just for those who want to know. =)
Now, when people make inserts, they usually make it such that the design will go around twice. This is to prevent the paper from coming up just a little short of being around the inside fully (whether by cutting, bad measurement, etc) and leaving a gap. As a result, only half of the image shows when the paper is actually being put into the pen. That's the reason for step 5. Now, for a design to "wrap" properly, the top and bottom of either half of your paper must tesselate. That is, if you cut your paper in half and made copies of that half and put them together vertically, they should meld seamlessly. In order to make sure that happens, the top of one half MUST have the same edge pattern as the bottom. Therefore, the easiest way to do that is to split that half into two and design that first. After that, when you put two of the fourths together and flip one, essentially the top and the bottom of that half will be the same and the image will wrap.
If I confused anyone, sorry. I'll post pictures with this if anyone wants, but I'm feeling lazy right now. >.>