Welcome to the fourm!
I just got a x120e unit from a forum member for $250. I have not been around to play with it yet since it just came back from IBM Ezserv (had to replace the keyboard due the left mouse button acting like the right mouse button). It has a dual core AMD 350 CPU and a AMD GPU. I can run some tests for you if you like over the weekend, just let me know what you want me to run. I don't know how the unit compares to the S12 ION machine. I remember when the ION was introduced on a HP netbook and reading on a HP forum, people did like the boost when playing games.
Can I ask what is your budget?
Talk to you soon,
701c, 600x, 240, T30, T43, T60, T61p (x2), T601 (TuuS Built), X61s, X301, X200T, X200s, X220, X220T, T400, T410i, T420, T530 (Quad), W530, T440p (Quad), W540, ThinkPad Twist
Sold: PalmTop PC110, T420