If you are changing the case, this job is easy as hell.
Any Socket 478 board will work that proc. Since the 1.6 is old, you don't need to search around for anything special. (i.e. 533 or 800 FSB support, 1MB cache support, etc.)
Memory may be the only problem. I'm guessing since it is a 1.6 and Sony, at that time it probably had SDRAM and not DDR. Finding a P4 board now with SDRAM instead of DDR is tough.
You may want to consider changing the CD drives and floppy also though. Floppy may not have a face on it when removed from the case. CD drives may have a bare face also.
