Creating permalink levels simply for SEO

Hi all,

Wonder if anyone can help with this – I’ve scoured the forums and Codex and haven’t really found a simple solution.

Basically my permalink structure is as follows:

/%category%/%postname%/

But I want to be able to add two extra levels to it myself, in the browser. So, something like this:

/mycategory/mypostname/123/anythingiwant/

The 123 refers to an id in my database (which does work) but if I attempt another permalink level it doesn’t like it. Basically I just want to be able to use the rest of the URI for SEO purposes, and not for it to redirect anywhere.

Is there a way to do this so it doesn’t matter what I write after the first 3 segments of the link?

Thanks in advance