Here's some tips that James has shared with me to pass on to you.
EntRef - Ever heard of this one? Nor had I and it's not documented. It's kind of a cheap block. It can only contain 1 item, Acad OR ACA. It doesn't have a name but you can create an object and copy it around. If you move the original, all others will move. If you alter the original, all the copies will be updated. Archidigm shows a possible use for the EntRef command here. (It's copying a downpipe around the building). You could use it for a text item that is repeated.
James, I had a quick play with an ENTREF of a window for the purpose of creating a window schedule and it seemed to work. The copy is not added to a schedule as it is recognised as a copy of the original, not a seperate frame. My schedule is set to automatically add frames and I also tried to add it manually. The EntRef updated in size when I changed the original but the dim's don't auto-update. Possibly you could construct a schedule and bring the EntRef in for the graphic but I could not block *1 the EntRef for auto insertion but at least there is a connection. The copy did not need the wall to anchor either. mmm... perhaps some possibility there for further exploration.
*1 Did you know that schedules in 09 can include a block!