Karl
I agree with David's comments.
A true PE12 rod is an animal that very few people can master and fish to it's full potential. I have one and whole heartedly admit that I'm yet to tame this beast... but boy does it look good in the rod rack!
Also, there arn't that many of them out there... with good reason.
Your Monster Mesh may well be a little on the light side... how do you find it?
If you feel you can push it to the max and you feel you still have some physical strength and energy left in reserve... by all means, you may need a heavier rod.
Brandon's sticky thread on rods is worth a read.
I will mention a few rods that I have had personal experience with that might be worth considering...
Smith Komodo Dragon - one of the more user friendly high end rods getting around... I really enjoy this rod when fighting fish and comforably use PE10 and fish it hard. I got my PB of 40kg on this rod.
Smith Tokara - I've used my mate's one and he also love's it... a little stiffer than the KD, but still nice in the hand.
Shimano Karbitsu Surface Monster - I found it to have some similar characteristics to the KD... maybe even a little sweeter. I just wasn't a huge fan of the longer than normal handle. It is one rod that I think you could fish PE12 if you wanted, but PE10 was comfortable for me. It's also a rod that's been getting a few reports of breakages... not sure why this has happened, but I can tell you my fishing buddy was skull dragging 30kg fish to the boat and was not gentle on this rod in any way.
Carpenter SP78H - Probably my favorite rod now. It's stiff enough to work decent sized poppers and isn't too angry on you when you hook a decent fish.
Anyway, if you do a bit of reading/research, you'll find that there have been many 50kg+ fish caught on PE10 outfits... if you chose to go PE12, then do yourself a favor and try borrowing a rod, fish with it and see if it suits.
Cheers Rob