On banners, logos and other images, the less text, the better.

All such items should, however, be direct links to something with a full text version. This might be hover-over text, a link or the package info page in the package manager. Long version, when in prose; shortest possible version when alone (i.e. as image).
Here's why...
Community Seamless Software Updates - quite a mouthful!
Community Update - sounds like a newsletter.
Community SSU - is understood by TMO folks only.
CSS Update - something to do with web pages?
- The notion of what it is cannot be succinctly conveyed using a partial acronym.
CSSU - although not clear to non-tmo people, is visually succinct. So long as links and mouse-overs all work, the longhand name will be evident to all pretty rapidly.

Consider, if this were permitted in OVI store, what's the simplest means of getting the msg across and still being accurate?
...mmm I wonder what loopholes could be found so the cssu repo installer could get permitted to OVI store mmm...

Anyway, colour coding is a good idea. Is the testing so dangerous as to need to be red? I thought it was "stable with rough edges", not "expect reboots daily". Why not maemo orange be good for testing and either CSSU yellow or a lurid green for stable?

... just thinking aloud

BTW thanks for doing images so we can thrash this out with some sort of context.