This would be neat too, if you ditched the ribbon and velcro and just wrote a letter, stuck some pictures inside, and mailed it to someone. Sure, it would cost a bit extra, but it would be an awesome thing to recieve in your mailbox!
I actually just did that. My friend and I always send "creative" stuff back and forth so I decided to send her one of these. I put different things in each pocket - - a letter in the first one, some drawings I did in the second, poems in the third, and newspaper clippings in the forth. It makes for an interesting letter.