Pino instead of Gwibber?
 

Like some here I have also heard about Gwibber on N900 and seen the "real" screenshots.

As some pointed out, Gwibber has become very feature heavy and some tweaking is most likely needed to tone it down a bit.

If I could code, I would get hacking right away, but I can't; so I thought I would at least come with a possible other alternative that might be interesting for a coder with a N900.

Pino - http://pino-app.appspot.com/

I haven't tried it myself, but it looks really nice and would probably be perfect on the N900.