Wow, truly impressive looking! Have you only gone with beads and such, or have you tried paper or fabric, and if so, how did those turn out?
I have done a few different things inside. Circuit board parts (probably my favorites), beads, keys, silk flowers, computer wires, nuts and screws (hardware), staples and tacks, nails and I even did some baseball cards. They all turned out great. The hardest ones were the baseball cards. They tend to "float" more than the rest and the edges start to saturate, but for the most part, they turned out pretty good. If you check my other posts, you can find the "computer parts coasters". Thanks for looking.