How to build a snowboard bench?

HELP! Where can I buy/build a self adjustable seating patch for piano bench?

• I am a pianist and my body is very short. I like to keep my elbows level with the keyboard, however, even when a self adjustable piano bench is available, the toppest it can go is still way too low for me, I often need to sit on a book to practice, let alone perform. Does anyone out there have this problem and found a solution? I don't want to bring a phonebook upstage when I perform since it obviously look odd. I want to find a black platform foam that's lightweight so that I can just sit on it. Do you know where can I find one? Even better, is there a device out there that has the dimension of a book and you can adjust the the height? Thanks.

• Answer:

  They make booster cushion for benches, here are links to different ones: http://lundbergmusic.iwebc.net/ http://www.pianobench.com/products/166