Maybe not Bada, but LiMo, and presumably now Tizen, is not just GTK. It also includes support for EFL (aka Enlightenment/E17), a project Samsung has been supporting for the past few years.* The EFL Webkit port is also progressing, also with Samsung support.

Hopefully being HTML5 buzzword-compliant doesn't mean they're dropping all support for native apps too.

* As previously discussed: http://news.ycombinator.com/item?id=2495826

Bada is not a full OS, it's more like Qt. Bada does contain a kernel out of the box afaik, but the kernel is pluggable. So perhaps Samsung can use Tizen under the hood, and Bada on top.