Here's the schematic and hardware layout for the <a href="http://www.casperelectronics.com/finished-pieces/speak-n-spell/c1-edition/">C1 edition</a> Speak&Spell, Math and Read. 
I still have a few finished units for sale. <a href="http://www.casperelectronics.com/for-sale-2/">see the for sale page</a>. If you have to have one and don't feel like making it yourself, drop me a line at pete (at) casperelectronics (dot) com<p>
<a href="http://casperelectronics.com/images/finishedpieces/speak-n-spell/Speak-n-Xbending/ASSEMBLYdiagram.jpg"><img src="http://casperelectronics.com/images/finishedpieces/speak-n-spell/Speak-n-Xbending/_ASSEMBLYdiagram.jpg" width="407" height="560" alt="" title=""  /></a><p>
Please read the notes for this schematic on the <a href="http://casperelectronics.com/finished-pieces/speak-n-spell/speakspell-bending/">Speak&Spell bending page</a> before attempting the modification illustrated above.