Perhaps not exactly on topic, I had Funambol working with the N900 not too long ago - it works in much the same way other SyncML stuff sort of works, just not quite the way you expect it will.

I stopped using it after a few days simply because it couldn't handle the entire contact card, only a small subset of it, and very poorly at that.

Although I never bothered to delve too deeply in to the configuration options for the N900, I got the impression they are different for every handset, so it's unlikely that selecting a different model will come with any success at all.