Or is my thought too simple for SEO on IIS6 using readable URLs?

Hi, just wondering and new to SEO with URL’s.
My situation is a bit complex to make it simple for me
I have a server running IIS6 and using php/mysql for years now. To optimize for search engines, I noticed some techniques like 301 redirects. The only articles I found for IIS have solutions for .net related scripts.

I think I have a trick for my situation, but before making it, I’d like to hear your oppinion about it.

If I would make urls like: some url://my-first-seo-url
It now would turn into a 404 page. But if I would change the 404.htm into redirect.php in the config, I could then process the url and query the database to get the right url and make a 301 redirect to it.
Would that enhance my site for search engines?

In this way, if my simple thought would work, it would make it a lot easier for aspx, php, cgi or whatever scripting engine you have running on your IIS6.

So if I would use my titles for every article on my site to be a unique identifier like:
some url://this-is-a-briljant-idea-20090101
Then I only would have to strip off the dashes and process the url to give me the title and date to redirect to:
some url://index.php?id=12345

And would there be a difference using:

this/is/a/bad/idea

or

this-is-a-better-idea

Just my thought, hoping for some feedback.