I'm not talking about the window size

I'm referring to the object size. Here's a http://i855.photobucket.com/albums/ab118/AndalayBay/Oblivion/SizeColumn.jpg. In itself, it won't be very useful. However I think it would be very handy for categorizing a bunch of items, which is what I want to use it for. It seems to be based off the model size. I have found items that have very similar dimensions in bhkBoxShape will have the same size. So even if the NIF is named differently, if the size is the same, you'll find that the actual dimensions of the box shape will be very close.
I have a slight feeling I'm going to have to ask the OBSE guys to add a function for it, or write my own plugin, if I can even find the element in the API.
Bit of an update: something like this will be added to a future version of OBSE. NifSE will also have some similar functionality in a future release.