Domoticz

I'm currently running the latest stable on port 8080 of a raspberry pi.

But I would like to be able to also run a beta version on the same machine, and be able to switch between them easily. My thoughts are to run the beta version on a different port.

Aside form the port, I guess it would be best to install the beta in a separate directory, such as 'domoticz-beta'.

Is this do-able, and advisable?

In theory, yes. You're likely to find that connecting both instances to the same hardware will be troublesome or (close to) impossible though.