I'm working on the web application based on Scala, Lift, MongoDB. Which hosting solution are you using for such apps? I have been thought about something easy like Heroku or even totally configured VPS.
What is most popular deploy tool in JVM/Scala world? E.g. I use Capistrano for Rails.
A Xen-based VPS is a good choice for Java based applications. Java will not run good on a OpenVZ based VPS.
Ang you also have the alternative to use Google App Engine or Amazon.