It really depends exactly what figures you want the pieces to be. i know that HOS has an Elephant and Hawk(?) for Seirawan chess (which is played on 10x10) a full set can be found here, or just the four extras here.
Where can I buy Fairy Chess pieces?

The 10x10 board is easy to find since that is the standard for draughts.
http://www.mastersgames.com/cat/board/draughts-checkers-10x10-folding.htm
For the pieces you might try mixing a Staunton set with another design.

That Seirawan chess set is very cool. I might have to look into getting that.
I mean, I could always use a checkerboard along with common objects (say, a coin, a paperclip, whatever). It would just be cool to have a whole set.

I'm sure there's someone somewhere who makes them, I've just never seen any other than the ones I linked to above.

I'm sorry, all I can think of is this clip from The Big Bang Theory..

Thought you'd like that. I turn chess sets as a hobby, in my upcoming set I plan on have gator headed knights carved and turned to replace the prototypical horse headed knight. All the moves, etc will stay the same though, so not really fairie chess.
Omega Chess also has two new pieces (the champion and the wizard) that you can use as other fairy pieces if you want. It also comes with a 10x10 board (with extra squares in the corner, but you can just ignore those if you want).

Seirawan chess is an excellent variant. It's actually played on the 8x8 board, and the hawk and elephant appear on the board as you develop your pieces.
For anyone who's interested, I'm also starting a free Seirawan chess periodical

http://en.wikipedia.org/wiki/Fairy_chess_piece
Where would be the best place to find pieces like this, or a set (with a 10x10 board)? Just curious.
I believe (musketeerchess) will lead to links where you can buy variant chess pieces, and also explains their moves. I think it has a collection of about 10 interesting pieces but is still missing some of the newest, such as the huygens. 😽

http://en.wikipedia.org/wiki/Fairy_chess_piece
Where would be the best place to find pieces like this, or a set (with a 10x10 board)? Just curious.