Most of the maint pages can only be accessed by maint personnel as per the a/c maint manuals, flight manuals, etc.. On a CRJ700/900 there is a switch behind the capt chair on the bulkhead that will display the maint menus/actions on either PFD1 or PFD 2. This would not be something you want to do in flight. Not to mention Bombardier prohibits the use of the "lil red switch" by flight crew.
Just another tid bit..
On the DHC8 100/200's, next to the captains left knee there are 4 switches for maint use. 2 are for trimming the engines and the other two are for pulling/clearing fault codes from each engines ECU. A bit more old school than modern boeings & regionals, but very useful when troubleshooting engine problems during runs and rigging.