Something like Amazon Matchbook is a better solution in my opinion.
What you're proposing though is like inventing a particularly-complex-to-manufacture CD... after the iPod. If you want the convenience of something that not only has resizeable, searchable text but also weighs very little, then any current generation reader offers the exact experience you're looking to replicate, except you only have to buy and carry around one of them.
Even if and when we get to the point where e-ink screens can be manufactured for a dollar, I don't see much of a market for one-book readers.