If you mean version 5.1 it's been available since the 12th of December :) To be exact, the most recent version right now is the version 5.1.1. It's downloadable here. Also, refer to this news for more information.
Regarding the tunnels etc. RUT does not create a VPN tunnel. However, if the network environment on either side (remote or local) is restrictive and only allows port 443, the program automatically uses port 443 provided that you connect using the Internet IDconnection.
Also, in the version 5.1. proxy settings are available for both Server and Viewer.
That will take some effort but we'll try all we can so that this feature is available in the version 5.2. I agree with you that it's very handy to print something out from the remote PC to the local printer once in a while.
This is a bit tricky given that Dropbox or Box.net already exist that do the sync task perfectly. The File Transfer mode was primarily intended for occasional file transfers, not as a full-fledged sync tool, as this is much better done by specialized software or cloud services. But we'll see what we can do.