Anyone know what the largest centerfire pistol/revolver cartridge.  I am refering to cartridges designed to be used in a handgun, not rifle cartridges wedged into enormous cylinders like the BFR.

.50 AE? (biggest waste of a brass)
.480 Ruger? (most controllable)
.454 Casull (biggest Recoil OUCH!)

Not counting any of the flare guns made through the years, the 50AE is the big mamoose, far as I know.

Biggest production one would be 454 casull.  Corbon has a loading with 1907 ft/lbs of energy which sends a 265 grainer at 1800 ft/sec!!  The 50 AE does rival the Casull though.  There are other non-production calibers with even more power I hear.  People talk about the mystical fist of god which is call the 475 Linebaugh:-)

I think you should limit this to production models and the .454 would lead.

Quoted: I would guess that the current largest centerfire pistol cartridge is the 50 AE since over that it would be a "destructive device," right?

No.

According 2002 Gun Digest. The 454 Casull is the "strongest" of the .480 Ruger, .454 and .44 mag.  
It didn't mention the .50 AE, but I don't believe it carries the punch of the Magnums or Casull

Biggest currently made? or biggest ever?

Biggest bore currently made commercially is .50AE, but Linebaugh also makes a .500 for revolvers that is wayy more powerful.

The biggest bore ever in a metallic cartridge handgun, that was NOT ever a rifle or pistol cartridge was the .577 Boxer cartridge for the Webley Mk I revolver in the late 1870's.

Had to qualify that because Lancaster also made a 4 barrel break action pistol that took .577 Snider Enfield rifle cartridges starting in the late 1860's and going into the early 20th century. And even today a true masochist can order a .460 Wetherby in a Contender or Encore if he wants.