Hmmm...Having read last two posts, I'm now thinking shifter registers x 2
Found a great tutorial: http://bildr.org/2011/02/74hc595/
Impressed...I now know what a shift register does! 8)
I'm getting the SparkFun Inventors kit, which happens to come with a 74HC595, so I can at least get something running as a prototype (of a prototype!) before commencing the build.
Thanks again all...Excited and looking forward to getting started on this! 