Here at our company, we have an Excel spreadsheet we made from input from other sources. It works really well. There are times we need to link these together to see the load on an MCC or larger distrbution panel. As Scott says, thats when you need to know how to do it, although it is not difficult. I can link an entire plant toghether and give a connected load and an estimated demand. I can play other games with it if necessary, like making charts of various descriptions, etc. I use lookup tables to get HP amps, to size conductors, circuit breakers, etc. I am working on using another lookup table to incorporate motor starter sizing and overloads.
But all that aside, I still like to see what others are doing so as to spice up my own ideas. Keep up the good work.