I´ve been using www.togglemobile.co.uk
for quite a while now.
You can have 9 simultaneous numbers on one SIM (including a Swiss number), incoming calls are free in quite a number of countries (most of EU; USA; Australia...).
When abroad I just divert my "usual" Swiss number to my "toggle" Swiss number. The divert counts as a usual Swiss domestic call, which is included in my monthly package anyway. So I effectively receive calls on my usual Swiss# for free.