This was Nokia's reply to my query:

"Based on your concern, the navigation feature is currently not available on the N900. Unfortunately, the current version of Maemo, the software that powers the N900, does not support navigation. With Maemo 5 we prioritized development of those areas that we felt would be the most important for the target audience of this device. This means that Maemo does not yet feature support for the full range of services that our other Symbian-powered Nseries devices might have. However, naturally, we’ll be working to increase support for all Nokia services, including navigation, as we go forward with Maemo"

Nokia are testing the latest Symbian version of Ovi maps, so I guess any QT/Maemo/Meego version is some way off yet.

What interests me is the claim that "we prioritized development... for the target audience of this device".

If effective satnav, a fully-specced calendar, and the myriad of features found as STANDARD on lesser nokia phones are not priority for a premier (if not flagship) device then what was the target market for the N900?