Avoiding a flat share but ending up in one room digs... check out Swiss Star apartments in Kloten. CHF 1600 per moth, quite steep though.
I used them for a few weeks while geting myself sorted, And I was at the same Opfikon Investment bank type place you'll be at....
I mention them 'coz they have wifi throughout now.
Perhaps not what you're looking for, sorry if useless advice :-)
Hopefully, I can redeem myself with this:
http://swisswiki.ch/index.php/Accommodation which has info on flat share stuff
Incidently, the Imagine bar in Zurich main station has free wifi; just see how long you can make a beer last...
Cheers