Re: Bowing to Kamidana/Kamiza
Just an extra note on "kamiza". "Kami" is an old Japanese word to mean "upper, higher", used for many different things, and thus distinguished by different kanji. For example, there's the physically "higher" - 上, and the metaphysically "higher" - 神, and the socially "higher" - 守, and the "highest" part of your body, the crown of the head - 髪.
The "kami" in "kamiza", refers only an "upper" sense in social context. The "seat of honor", as I suggested. Japan has its own share of devout Buddhists, Christians, and even atheists. Even in these people's houses there is a kamiza (and shimoza). It's simply a layout of a room according Japanese etiquette. Indeed, someone who knows the etiquette can go into any western house and point out where the kamiza is, or would be if the person living there followed Japanese etiquette.
Just last week I attended a meeting at my school, and I could tell before anyone sat down who would sit where, simply based on an understanding of which seat was the kamiza (and thus where the principal would sit).
So while kamiza and kamidana share the same "kami" sound, "kamiza" has no religious significance, and neither does bowing to it.