I have had a dream, opera mini on the n900.
And three brave Russian guy helped me realize my dream (©S0d
®Ale}{(is) ®Voobsche).
They wrote an intermediate proxy server (on python) that can connect to the opera mini server, and minimize traffic.

Here's a quick tutorial:
1) Download the OMPD - tHE oPERA mINI Proxy (python 2.5 required)

2) Unpack archive anywhere.

3) Run server with command: python ./ompd.pyc -d (without gainroot)



4) Go on localchost:8080 Check availability, make the necessary adjustments.





5) Go to the "expensive" connection settings(setting>>internet connections>>connections>>"expensive" connection>> edit >>next>>next>>advanced>>proxies), GPRS in my case, and and in the Http proxy enter: 127.0.0.1 port 8080


6) All your browsers will work through operamini proxy (Opera Mobile and MicroB works fine, others not tested)
and you have the cache



7) PROFIT))

Everyone a good day!

OPMD-proxy official source

Google and this post screenshots (MicroB)