HP are really splashing out on WebOS as their smartphone/tablet play, and they're supporting a community much like maemo.org (PreCentral.net). It might not work out for them, but you can guarantee investment in the platform for at least the foreseeable future. Also, as has already been said, the stack isn't too different from Maemo.

I'd like a MeeGo phone with a hwkb supported by an enthusiastic company, but life isn't about what you want - it's about what you can have. I think the Pre3 is the nearest thing to an N900 successor we'll see this year.