(I credit Monica Geller for first making mismatched chairs cool, btw.)
Craigslist is a great source if you want to pick up some odd chairs to recreate a similar look. You can often find chairs in odd numbers for a really great price. I just saw three of these, for example, on my local Craigslist for $20 each:
And, another listing for three side chairs and one armchair that would only need some new fabric:
And, you can always paint them for a quick update. Remember the chairs I bought for our old dining room for $12 a piece? You know I believe spray paint can fix anything.