Like Chris, I've deployed Blacklight on Heroku, and this thread
(particularly Rosalyn's message) has gotten me to write up a quick
HOWTO on the Blacklight wiki [0].

For Solr hosting I've used both a VM that I run (on Slicehost) and EC2.

Mark

  [0] https://github.com/projectblacklight/blacklight/wiki/Blacklight-on-Heroku