The 32 vs. 16 GB microSD card thing, I think, is like MeeGo on the N900. Nokia never officially said they support it, but it runs just fine. I think the N900 was released before 32GB microSD cards went on sale - so the people calling the shots said screw it, we won't say we support it because we couldn't test it so we don't people coming to us later complaining about 32GB microSD cards not working, just in case it turns out they don't.

- Edit -

People above me, namely the guy about how it's linux and it's supported much higher capacity cards by then, have already given better answers.