I did this a while ago thanks to info I found on this site - so just thought I would share...
First I found a dead white PCE on ebay that was very cheap. Replaced the fuse and that got it working fine (Couldn't use the RF output being in the UK, so tapped the rear audio outputs to tell if the unit was running a game ok or not).
Then did a SCART RGB mod in the place of the old RF output. Running out a dedicated cable may have been neater, but I wanted to be able to use this in the cd briefcase too so went for the large SCART socket.
The region mod is a long 16PDT switch that toggles, had to add some rigid support at the opposite end so when it was pressed it wouldn't get stressed over time.