finger puppets are something else i want to try.
www.gardenofpraise.com has some good stuff, too. type 'piano lessons' into the search box. it's not printing like it used to. but, click on 'teachers' if you want - and maybe you can get some stuff by scrolling down to 'music' something or other. i used to get exercises and flashcards here.
i can speak from experience, that parents will love it if you make them write at least their first name on their workpages. any repetition of writing their name is good for them at this point. tracing their hands is one project. writing letters (dotted lines) and corresponding place on treble staff. putting stickers of letters on the correct notes on the piano from bass to treble (starting with low A in bass). some teachers don't like stickers. i don't care as long as they can come off later without a lot of effort. there must be some good kinds of 'laminate type' stickers that peel off easily.
there was another thread about things to do to keep kids excited about music. my daughter is most excited about getting mail. send your students postcards of composers? you can make lots of crafts one day /too. maybe the song day can be a 'letter' or 'color' day as well.
'dancing shoes' is another concept that i havent' gotten off the ground yet - but would involve something like the game of 'twister.' in fact, you could use the twister idea floormat - but make it a long long (2-3 octaves with mid-C in the middle) keyboard (paper) and large keys with feet placements walking up and down the keyboard. then, you could play and say a note ('A' - play note) and then have them run to the key. and stop on it. later on, try to see if you can play a note and have them guess what key to stop on.
at these ages - kids love prizes, too. even for good behavior. one choir teacher i knew used 'good behavior bucks.' if they were quiet the entire lesson and were able to answer questions (even if wrong answer) they got some 'behavior bucks' which were tradable on fridays (or last lesson) for pencils and erasers and little stuff. sometimes there were big ticket items (such as a free ticket to a concert - etc).