A bunch of apps are out there where you can select a picture and make it your operator logo. Some also come bundled (for instance, FExplorer, one of the best S60 file explorers, has this option built in). The pic will eventually be disproportional and not very nice unless you work on the dimensions.
My challenge was to change MTC Touch's operator name and make it look the same, i.e. have the same background color and pattern, and font used by nokia to display operator name. It took some brainteasing, but with a file explorer (like FExplorer), a S60 screenshots app, and some photoshop i was able to pull it off.
Look at the pictures below
Before and
After
If anyone interested in the procedure, let me know so i post it here.
Cheers