Is there any really good timeline software?

Timelines are a great way of organizing information and the computer gives the possibility of really making them useful. Here is what I have in mind.

Each entry has a date and optional time, description and detailed narrative. Entries should have tags and levels, with the option of linking a lower level entry to a higher level one. You should be able to select the level of display. Choosing a lower level would optionally show everything at a higher level. You should be able to choose an event at one level and drill down to linked lower level entries.

You should be able to restrict what you see by combining tags. You should be able to choose any logical combination of tags – (German or Austrian) And Music.

You should be able to limit the time period viewed and be able to zoom in and out.

For any timeline restriction based on tags, level and time range, you should be able to create a new timeline with the chosen characteristics and you should be able to merge two timelines. It should be possible to view two or more timelines simultaneously.

It should be possible to embed links in the narrative to text or multi-media.

I am guessing no such software exists. Do you think it would be worthwhile to create it?