Just came across this variation on the wooden dummy. It's called the Tec Board. Looks interesting...but pretty expensive.
http://www.everythingwingchun.com/SPRIN ... rd-lrg.htm
http://www.everythingwingchun.com/Wing- ... -s/322.htm
It looks good but I don't think it gives the proper feeling of a strong wooden arms. Spring arms are too soft and yelding. In my opinion it's good for beginners.