As a matter of interest for anyone planning an integrated design such as Glen's - with the Temp Controller and a PWM module boxed together, I came across this cheap digital temp controller board in a rummage through the dreaded ebay -
http://www.ebay.com.au/itm/390686340888
I've ordered a couple to play with and will see how well I can integrate them with the PWMs I already have.
I'll let you know in due course.
Peter