If somebody is ready to help a project:
We need GRUB to be extended a little so that it can load stage 2 and
kernel from Phantom
disk. Headers and examles of code are in the project repository:
http://code.google.com/p/phantomuserland/source/browse/#svn/trunk/tools/fs
pfsextract has all the code needed to read from Phantom 'FS' - this
code needs only to be added to GRUB.
Next task would be to write tool to insert kernel and boot modules to
phantom disk (image), which is easy too.