A fellow member at AUGI and from New Zealand, Guy is a programming consultant for Revit. He has unselfishly shared is knowledge and insight at AUGI ever since an API appeared in Revit. Some time ago I posted a thread at AUGI's Revit API forum asking if anyone had created a routine to count selected elements. It might startle users of AutoCAD to learn that there isn't a "list" command that will tell you how many things you've got selected. There is a presumption that you will use schedules to report data like this in Revit but sometimes it is useful to select some stuff and "count" them quickly.
As it happens there is an example software project that nearly does exactly that in the SDK (Software Development Kit) that is part of the content that comes with Revit. Guy was good enough to tweak it a bit and post it at the AUGI forum for me and anyone else who goes to the trouble to go there and get it (have to be a member to download it). The thread title is: "API Project: Count Selected Elements".
Using it is quite simple, select some stuff and launch the tool, you get a dialog box that lists the elements you selected plus a little bonus information.
I haven't add a chance to confirm with Guy that I can share his contact info here yet. Will do if it is okay, though I doubt getting inquiries is objectionable. In the meantime send me an email and I can put you in touch with him or simply send him a private message via the message system at AUGI.
Thanks Guy, I use it quite a bit!