Replacement SmartFade power supplies - what to look for

Just the rubber jacket around the plug is different?  No problem.

If you're saying the actual barrel connector is a different size (and thus won't fit), then of course it will not work, but that's not what it looks like in the picture.

The barrel size is the same but the interior hole in the barrel is very slightly smaller which is keeping it from fitting. Is it possible that it's a manufacturing defect?

Ah, well if it doesn't fit, it doesn't fit :-).

There are many sizes of barrel connectors like these.  I'm surprised that this manufacturer puts the same part number on supplies with different connectors!

The correct answer, courtesy of ETC Engineer Colin Beranek, is:

The Smartfade power connector is a standard 2.5mm x 5.5mm connector. The key is more the length of the barrel (the silver part that actually plugs into the console); that part needs to be about 14mm long to plug into the old (non-locking) connector.

That simple piece of size information solved my problems. Of course, it may be a standard size, but it's hard to find without having to buy bulk lots.