Followup on the Gossamer Gear Mariposa--the packs have arrived and they look just like what I've been wanting--a lightweight pack (18 oz.) with plenty of support structure. Thanks to the laced compression cords (not just straps), they can be snugged down to fit a smaller load quite easily. They appear to be just the right size for my two older grandkids (the 6-year-old is as big as her 8-year old brother and actually a stronger athlete, so everything is basically interchangeable). However, I need to take them up to Seattle and try them on the kids with a load, which will happen next week. I'll report back!