@cdrmb Thanks for reaching out!
To answer your question, no, none of the sleeping bag liners REI sells have full length zippers. The Cocoon Cotton Bag Liner/Travel Sheet has a 3/4 length opening with velcro closure, and the Sea to Summit Thermolite Reactor Fleece Liner has a quarter zipper.
The REI Co-op Helio Down 40 Sleeping Bag is a really lightweight sleeping bag/sleeping bag liner that has a full zipper and might be worth checking out, depending on what kind of conditions you are sleeping in.
Hope this helps!
Your question leaves me scratching my head wondering WHY you want a zipper? I have a mummy-shaped silk liner made by Cocoon that is inside my REI Magma 10 sleeping bag that has no zipper. To MEeee, any liner is merely something to separate MEeee from the interior of my bag. This keeps the interior of my bag clean, the silk liner is easy peasy to pull out & wash if it gets dirty or smelly from body odor.
Another "Why a Zipper?" question. I use a Sea to Summit liner in both my down bag and my synthetic bag, and sometimes, on warm nights, will start off sleeping in just the liner on top of my bag until the temp drops. I have never, ever, wanted a zipper. I use the liner to both keep my bags clean and also to add a few degrees of comfort.