I’m familiar with the meaning of -kun, -chan, -sama, -san, -sensei, and -danna, but the precise meaning of -dono eludes me. Based on the context I’ve heard it used, it appears to be used as a respectful way of addressing someone who’s younger than oneself and with some level of distinction or training.
For example, in Inuyasha, Kaede (an elderly miko, for the uninitiated) refers to Miroku (a young monk) as Houshi-dono. Do I have it right? What else to it is there?
Dono is a very formal personal suffix. In classical usage, it was used for people of significantly higher social rank than the speaker. In modern usage, it is somewhat similar to sama. While sama is used quite abundantly in business-client relationships, dono appears to be more popular in government circles.
In practice, that’s about it: it’s a suffix you tack onto people’s names on official documents. It has about the same level of politeness and formality as sama but with less deference.