Error Pages (404, general, DB etc)

[eluser]moth[/eluser]
I don't know if I'm alone in this, but I'm finding the error pages a bit painful.

I'm using a templating system to render certain layouts, and have a "general" layout that I would like to apply to all 4 error pages as supplied by CI (404, DB, General, PHP).

I know I can override the 404 in routes, and I know I could manually drop in HTML to the pages provided - but I don't want to.

I want to have an Error controller, where by I can attach my template syntax to each of the 4 pages/views.

Can anyone shed some light on how to approach this? I found the Exceptions class, but there's not a lot in there that's making much sense to me.