Maybe not the easy solution you're looking for, but there are inexpensive macro programs that allow you to create commands running in the background to launch when certain windows open. You can set them up to launch routines when you CLOSE windows, too in order to verify the contents of fields before actually saving the data. For example, I wrote routines that authenticate and/or standardize data for new customers, and do other things like use their "ship to city" to lookup and enter their sales tax district and rate from the California sales tax database before saving the data to QuickBooks. I find it great for getting around some of my QuickBooks pet peaves without having to change to a more expensive software.
The macro software is available free for 30 day trial online and costs only 30.00 if you keep it. Its called QuickMacros. I don't work for them, but I love using it for automating lots of things on my server and my laptop. It allows unlimited users when installed on a server, too! (Of course it helps to like some programming, too)
Craig