very nice. some remarks:
* did make sure the new partition offsets are aligned with the device blocks?
wrong alignment could harm performance a lot.
* you could provide a modified sfdisk dump so that users just need to run "sfdisk /dev/... < newtable" with the onboard sfdisk.
changing single partition ids with sfdisk can be done from cmdline, too.
IMHO it would be cleaner to have the extended partition at p3 and move home and swap one number up...
* I'd change the vfat partition id to 0c only after mkfs - it's safer

I think we should continue the technical discussion in the mailing list
https://garage.maemo.org/mailman/listinfo/moebian-devel
TMO is only good for smilies and thanks