I'd like to say that pushbutton mechanical locks are not all "pickproof". In fact, when I attended trade school for my second year we practiced "picking" the Unican 1000 and 7000 series pushbutton mechanical locks.

Now THAT's a cool feeling to open one of those babies up.
From what I saw at the trade show, a few of the high security locking companies are going to a combination of mechanical AND electronic access with their keys. One particular brand, (I got their brochure and will look at it later), uses electronics so that even if a duplicate key were made, without the electronics the cylinder still won't turn.
'Course, they aren't cheap.
Abloy uses 11 discs....and as of yet I haven't heard of anyone successfully picking an Abloy, Medeco, or the Assa V10. Miwa uses magnets for its pick resistance, but fortunately there are other mechanical defects which makes it possible to bypass the keyway anyways.
There's also Schlage Primus, and the new Medeco 3.
Master Lock has come out with a new higher security keyway that uses a tight keyway, spool pins, and a second shearline that operates two steel ball bearings that must be manipuated. Haven't got any so I haven't tried 'em yet.
Tesa isn't pickproof, they just use really tight keyways and spool pins, as mentioned before.
Also noticed Abus is using a very similar principle to Abloy now in some of their fancier padlocks...I'm going to look into that further.
Check out this list of other locks considered high security.
www.chez.com/montmare/hiseclox.pdf