Sorry to crash your forum, but I just finished getting most of my big sis stuff so I completely understand what you're going through!
One good thing to invest in if you're planning on making your big sis a lot of stuff is paint pens. You can decorate practically anything with paint pens, and mine pretty much paid for themselves!
Now some gift ideas...
-you can buy an inexpensive picture frame and decorate it with your paint pens!
-in our house, we all bought our big sis' clipboards and decorated the back with paint pens so our big sis' all had really cool clipboards for meetings.
-you can buy a plastic container, decorate it with your paint pens and fill it with candy
-get a small glass candle holder (at least votive size, perhaps larger), paint it and fill it with potpourri (which costs like a dollar at walmart for a bag)
also, it's really fun to make gifts for your bigs with your pledge class-- you can all contribute to the paints, glue, rhinestones or whatever materials you use which makes it a lot cheaper for everyone-- plus you're bonding with your pledge class!
I hope this helps a little