I was in the same spot, and my son is only in Kindergarten, however I read a suggestion that I found to be GREAT! Take digital photos of the stuff you really like/want to save/etc. and throw away the rest. Then you can make a photo book of artwork from 1st grade, 2nd grade, etc. and not have all that clutter. The books are easy to make and you can do it on Shutterfly.com, Costco.com, tons of sites like that...Also http://www.PrintArtKids.com, here is what they do:
We all treasure our children's artwork. Sometimes the pieces are large and bulky and aren't easy to display or store. PrintArtKids makes it easy for you to share your child's artwork and photos with family and friends everywhere!
Simply choose a favorite from your kid’s art collection, a favorite photograph from your kid’s sporting event, family vacation or other special occasion, even your own artwork, and scan it or take a digital photo. Then, select the item(s) you wish to order and... (read more)
Mission:
To preserve your child's artwork with useful, high quality products that can be shared with family and friends.
Products:
Your child’s art (or your own artwork or favorite photographs) can be used to create Notepads, Note Cards, Notebooks, Journals, Invitations, Thank-You Notes, Birthday Cards, Holiday Cards, Postcards, Gift Labels, Return Address Labels and Cards for any occasion.