ETA: Just re-read the thread and the ruled or squared notebooks I mentioned in my reply won't fit the "blank" part you specified. I don't think I've ever seen blank composition book. Maybe you could check with an art supply house.
EDITED EARLIER REPLY:
The Levenger Notablia notebooks only come in ruled or squared varieties.
http://www.levenger.com/PAGETEMPLATES/PROD...archClicked|i=2Even without blank pages, it does have a green cover so it looks more grownup than the drug store variety.
Of course, Levenger also sells a
leather cover for it (they pretty much sell a leather cover for everything).
They come in packs of two and are a bit pricier than the drug store variety, but you have to pay to look like a grown up.