In fact, by coincidence I too just completed the development work for a 89C51 PWM card for a LED PARcan prototype. My company, DATALITE, received a order for 200 LED PARcans to be installed in several Govt projects for architectural lighting. I prefered the 40-pin version since we need to provide a 10 way DIP for addressing as well as several LED status indicators....there was ample space and life would be easier.
Attached a url link to a photo of the proto
board

Ujjal