I feel a bit silly asking this, but here it goes:

When I want to use fondant or modeling chocolate, I roll it out on a standard silicone mat (Wilton has one, so does Ateco, Sweetwise, etc) to get that perfectly smooth surface. 

The problem is, when I want to cut the fondant (not trim fondant after covering a cake), I like to use something really sharp like an Exacto knife or razor blade to keep the fondant’s edges smooth; unfortunately, these also cut thru the mat itself. I’ve tried a pizza cut, which was okay, but it too cut into the mat. 

Anyone have any ideas about an alternative?

I found this acrylic pizza cutter from OXO onAmazon, and am wondering if anyone has tried it/ if you think it has potential: (http://www.amazon.com/dp/B000AN0YYY/?tag=cakecentral-20+pizza+cutter)

Another option I found on Sugarcraft, a knife on 1 end, scriber on the other: http://www.globalsugarart.com/fmm-sugarcraft-knife-scriber-tool-p-17240.html

Anyone have other ideas, or experience using one of the tools above and can offer feedback?

In a different conversation thread, some suggested using a self-healing mat, so you could use an Exacto-Knife; however, the consensus seemed to be that self-healing mats are NOT food safe

Thanks everyone!

use a different surface like a cutting board

I also use an extractor knife to cut small fondant and do that on my work surface which is Granit. Just make sure it's absolutely clean before putting any fondant on it. You can buy them in square feet pieces at the shop as well...

I have that oxo pizza cutter and it's not sharp, but it cuts well--hope that makes sense.  I'd suggest using that to take off most of the excess and then transfer the cake to another surface that can handle a sharper.  I do something  that

I do something like that and it works well. 

I use a marzipan knife to cut fondant.  I have had mine for several years now and it is brilliant.  Much better than pizza cutters, sharp knives etc as it cuts cleanly through fondant without dragging the fondant but as it's plastic it doesn't cut through the surface below.

For me a marzipan knife is an absolutely essential part of my kit, once you have used one you will never go back to using knives or pizza cutters.

Thanks so much to everyone who answered! So what did I do?

Option #1 Smooth granite or marble slab (thanks Julia1812!)

Pros: Can cut with anything, razor blade, Exacto knife, pizza cautter, etc; super easy to clean with a sponge and/or hot, soapy water

Cons: It's HEAVY! And especially if you want to have lots of room to cut on, this can get really hard to move (unless you have smooth granite countertops, in which case you have no problem); it can get a bit expensive--if you want to get ahold of one easily, like at Sur La Table ($59.99). I'm sure if you put some time into searching for a piece directly from a granite/marble store/wholesaler, you could knock quite a bit off of that price, since people have smaller pieces left over from big kitchen/bathroom/etc projects (also, keep in mind silicone mats that are large and of good quality are just a bit cheaper or cost the same amount); lastly, I choose not to go with this option simply because I didn't have any space to store it.

Option #2 OXO Pizza cutter with acrylic/plastic wheel (thanks for the feedback maybenot!, who uses and like it)

Pros: If you like cutting with a pizza wheel, this one is for you. In most cases it won't damage silicone mats, it's designed not to, so you really have to be pressing very hard to cut your mat; also, you don't just have to use it for cake decorating--it cuts pizza too, and is safe for non-stick pans; it cuts fondant/gumpaste, etc very easily, but you never have to worry about cutting yourself; lastly, it's not very expensive (under $15)

Cons: You can damage your mat, if you get carried away and press down very hard; again, if you like using a pizza cutter, it's great--but if you don't, then you won't like this either.

Option #3 Marzipan Knife--also called Almond Paste Knife, esp. in the U.S. (thanks 810whitechoc!)

Pros: I LOVE THIS! It took me a long time to find, because I was searching for a marzipan knife, as it is called in the UK and Australia, I think; once I started searching almond paste knife, several options for buying it in the U.S. popped up, including on Amazon and Food Equipment Direct and Paderno USA; it's not too expensive (about $9-$19); it works and doesn't cut your mat; and it's easy to store.

Cons: Ummm... it is another tool to buy, and yes, it sucks having to pay for shipping (although it's eligible for Prime on Amazon); I'm sure there are other downsides, and I'll update this post if I run into any trouble.

Thanks so much to everyone who responded! I feel like I just wrote a short novel--sorry it's so long!--but I firmly believe in internet karma, specifically CakeCentral karma, so I always try to answer questions with as much info as I'd like to see if I came across  the post with the same question.

Alexandra