Update status screen has poor accessibility

This didn't really hit home until I tried to write a section about this screen for the Lullabook.

Putting this screen into text is impossible without either mentioning:

a) the colour (which goes out the window entirely depending on the theme, and is useless to someone by a screen reader), or
b) the icons (which are lacking alt/title attributes and thus not visible at all if images are disabled or if viewed by a screen-reader)

The message itself on each row (esp rows that need updating) also varies depending on what's actually wrong. Looking at the defines in update.module, it looks like there are something like 10 possible statuses that could be displayed here.

I'd advocate at least one (preferably both) of the following:

a) Put alt/title attributes on the icons, at the very least. That way I could mouseover them to figure out what "class" of error I'm seeing (info, warning, error).
b) Put "Error: " or "Warning: " in front of the status if it's not a-ok. For example, "Warning: No available releases found", "Error: Update available", and "Error: Security update required!"
c) Any other bright ideas one might have.