Just thought I'd share this in case someone is thinking of doing the same. Basically I managed to register with my local Kreisbüro in Zurich as a 'floater'--i.e. having no fixed abode. I mentioned that I am in a WG/flat share until the end of the month and I didn't know my housing situation after that. She suggested that she can put me in the system as having no fixed abode but the maximum time permitted for this is 6 months. The only thing I required was a contact person who lives in Stadt-Zürich. Not sure if everyone can do this and nor am I sure if it works in another gemeinde and/or canton. I have a C permit.