I think your reasoning is sound. Especially if you can eventually bypass all the BB stuff and make it straight up android 3.X machine. I'm in no way saying I'm anti Ipad, I just think at this point I'd rather hitch my wagon to google than apple.
Something about the locked down itunes apple way rubs me the wrong way, I get the sense the android community resembles more of the open source free software way of doing things.
I guess your price is $599 + gst if someone wanted to buy a playbook and trade it to you for your Ipad. problem solved.
I think your biggest problem is finding someone who actually has a BB playbook.
