You do realize that the current tubmail notification icon only appears after you visit your character page, right? And not when you get new tubmail?

It’s no doubt designed that way as a performance consideration. To have to poll tubmail every time the forum header is loaded would put quite the demand on the server, let alone having to hit all those other things you talk about.

However, a potential way around this would be to modify the same table which holds the remaining forum visits to also include flags for all these things, and update those flags using triggers on the appropriate other tables. Not sure how much of a hit that would be, but my guess is it would be within tolerable limits. Then the header code wouldn’t have to hit any additional tables.