Hello scpc,

I am not familiar with Bitnami, but as long as you can download the files and databases, you can transfer the sites.

Here is a link to Concrete5's official Hosting page:

http://www.concrete5.org/marketplace/hosting/...

I work for Web Hosting Hub, and you have the ability to password protect a site, so it can only be accessed with the password. It can then be removed when you are ready to go live. Bitnami most likely has a similar option, but I was unable to find a guide on it.

Here is a link to our guide on moving a Concrete5 website to us, it explains the transfer process using cPanel:

http://www.webhostinghub.com/support/edu/concrete5/get-started/move...

I hope this helps,

John-Paul

An easy way to copy a site from one server so you can install a clone on another server is with Backup Voodoo (I am the developer).
http://www.concrete5.org/marketplace/addons/backup-voodoo/...
Even if you decide not to use this, the documentation page contains plenty of info and links about cloning a site.