Interesting part : "So we’ll start with one device, which we’ll announce soon, and afterward other devices will follow."
@wicket: You are free to discuss this problem with Mer developers on the mailing list or the IRC channel. I think there are good solutions for that - to make some metapackages with bundles - default with some packages restricted to GPLv2, and optional ones where those packages will be replaced with updated versions even if they are GPLv3. So if vendors care - they'll use GPLv2 bundles. And if not - they'll use unrestricted ones. And users will be able to simply replace default ones with optional if they need to.