I think it would be really great if you'd manage to bring that to life.
Two other projects I'm aware of and that might be helpful in your endeavour are
a) Mark Jason Dominus' Rx debugger (http://perl.plover.com/Rx/) (seems to have been discontinued in 2001 ?) and
b) Chapter 11. REGULAR EXPRESSION GRAPHER of Steve Oualline's "Wicked Cool Perl Scripts" published by No Starch in February 2006, which is available via http://safari.oreilly.com/1593270623