egg tamagoyaki

Egg tamagoyaki... ideas???

Hi,
I've been seeing that this is a regular in a bento. I also saw that bento no. 64 made a egg tamagoyaki with nori in the middle. Here's my idea... couldn't you use other ingredints like bacon or sliced ham in the middle of the egg tamagoyaki?
If so does anyone have any idea's about more ingredints???