There's a company called Mobiclear working on exactly that, but they're so small (and poorly managed) right now that they'll probably go bankrupt.

I have the Sony reader. Cost justification is only part of the equation. But I do like that Sony gave away 100 free public domain titles with the reader. Sure I could find them on the web and read them for free already, but if I wanted a "take it with me" version I would have probably shelled out $4.99 for a paperback. Of course, if you don't read the classics, its moot, but I felt like I got a good $100-$200 worth of free books if I consider my own valuation of them (I might value the Poe collection at $10 but another book at $1). Top it all of with the fact that I'm still saving on a per title basis and the Sony reader is cheaper than the Kindle and I feel pretty good about the purchase.