[thaeli]

DOD transferred two "obsolete" KH-11 spy satellites (which are pretty much evolved Hubbles) to NASA in 2012. They've been in storage since. So the scope for a "new build Hubble" is putting instruments on those sats, launching them, and supporting the ongoing mission. That's still substantial, but much less than a new build from scratch.

[ISL]

One of them is, as far as I know, now dedicated to WFIRST:

https://spaceflightnow.com/2016/02/18/nasa-moves-forward-wit...

[kevin_thibedeau]

It was just the mirrors. Earth observing telescopes aren't useful for deep space.