I believe there's a member here that has one of those vintage guillotine's. Similar to what jitterbug linked above on ebay, but larger. I think he posted pics, but I can't for the life of me find it with the less than stellar search engine this site uses. I'm not certain how functional it is, but it is a great, collectable piece. This guy, whose name escapes me, does a bit of selling so you maybe he'll come along and post. Now he may not be interested in selling and you may not be interested in the price if he does, but it would be fitting if came and posted some images to the thread.
I smoke a lot of plugs, bricks, ropes, etc., and what works for me is a good old fashioned meat cleaver for the big jobs. Like when I want to cut a large brick down to a more manageable size. And nothing beats a good sharp pocket knife for shaving off thin slices of flakes or coins when you're ready to pack up a pipe and puff.