in reply to Pure Perl or the toolkit?
Since you're already using make, why not use install as well from within the Makefile? install should be available on most any system that has some form of make avaible. That seems to satisfy the required simplicity as well as being fairly portable. Instead of worrying about whats missing in File::Copy, just add an install call to your make target like so:
FILES=/tmp/one /tmp/two /tmp/three DEST=/tmp/mounted_image install: install -m 0755 $(FILES) $(DEST)
"Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic."