Are you talking about the early cell phones that needed a pack to carry with it?
Maybe in some jungle of a 3rd world country, there is a tribe of monkeys that sells those to the hippos because they don't know any better. But I doubt any humans are out there running a network for those phones.
I'm sure you can buy one, and maybe it will even connect to some service out there. Would be fun to find out if you managed that.
Here is what google found http/www.google.com/products/catalog?q=bag+phone&hl=en&rls=com.microsoft:en-us&prmd=ivns&um=1&ie=UTF-8&tbm=shop&cid=11485637888160171967#