Any chance of the 5S' entire screen being made of sapphire crystal?

Seriously, what are the chances?

I was reading the (most recent) thread regarding the potential price of the iPhone 5C, with me arguing that Apple couldn't make an iPhone 5C that costs a lot less than maybe $450 because there isn't much to cut out. I don't really care about internal specs (it just doesn't matter to me), but if Apple makes a 5S with similar internal specs and charges the same price, they could very well justify that to customers by making the entire touchscreen out of synthetic sapphire crystal.

The current rumour is that the fingerprint reader (Home button) would be made from sapphire crystal, but would it be possible for Apple to make a crystal faced iPhone?

For reference purposes, keep in mind that with regards to watches, it should cost ~$30 to replace a cheap crystal face on a cheap watch, while sapphire crystal may cost $60 on the low-end if your watch is a Tissot rather than a Baume & Mercier (which will cost more).