I was planning to put the larger tires on the front after reading above, and it sounds like that is going to be a pretty expensive deal - having to purchase new wheels too. Tirerack.com does not seem to have them. Is there somewhere else I can look? I'm really glad to have this info. The place I went to get tires said the larger ones would fit?!
Check this SCoA thread: http://www.smartcarofamerica.com/forums/f64/you-member-i-can-rotate...
Probably the easiest and cheapest way to get larger tires on the front is to fit a pair of stock rear wheels/tires. You can always go to larger wheels/tires all around but that adds $$$. Tire Rack should have the stock rear tires available; check on eBay or the SCoA Marketplace for a pair of stock rear wheels.
I decided to go with the tires as-is for now. Next time, I'll reconsider. It's too close to Christmas! I'm obviously not a techie with the car though I did install my own cruise control from Smartie Parts.
Go to Tirerack.com and they offer several brands for the smart. I bought the Blizzak snow tires for the rear and the conti's and/or the Kumho for the front. Delivered to my home the next day. Took them to Discount tire and had them mounted and balanced for $30 per pair.