Ok, so some good news:
1) All Kindle versions (US/Init/DX/DXi/DXG) uses the same kernel. That means I do not have to recompile the recovery kernel and risk bricking on other devices. The kernel I test on the K2 should also work the same on other kindles.
2) It SEEMS from the DXG one of you provided that the DXG has the same FS as the Kindle 2 US (with the exception of one library that handle International modem).
This means that I can, more quickly, make the DX versions and that minimal testing would be required on the DX (after K2US works).
Here's what I still need:
-rootfs image from Kindle DX US
-rootfs image from Kindle DX Internation
-rootfs image from Kindle 2 International
(or a broken kindle you can send me if you can't extract the image)