More than a year after this question was first asked, it doesn't appear to have been answered. I have also been unable to locate any guides for migrating from LPC2468 to LPC4078.
The marketing/datasheets/user guides for LPC407x/8x all state that it is a "Functional replacement for LPC23xx/24xx" but there's no application note or migration guide that I've found which will help to make that transition. Please help!