If the 64MB are in one partition, it'd be enough for a full cardfs install.
It's also split in half - 32-32Mb
I just upgraded to Mandrake 10.1 over this past weekend so I don't have all my data in it's proper place yet... but IIRC the partition (mtdblock) layout of /root and /home on the C750 and 5600 are 'very' close in size. So I believe the cardfs would install to /home on a C750 and work very well (as it does on my poodle) if that's what your thinking of doing?
There's a thread here somewhere about how well the cardfs fits on the jffs2 partition /home on a poodle.
Sorry, we seem to have hijacked this thread.
Greg