accessible online surveys

Hi,

I've spend  a major part of my day trialling software for creating online 
surveys.  I have not been able to locate any that are particularly 
accessible.  Many will allow you to change the font size, but not do 
things like change the button size etc.  Does anyone know of a software 
program that creates online surveys that are accessible?

Cheers, 

Amanda Bow
Environmental and Social Research
Bayside City Council