You will hardly find a provider who assigns numbers from all these countries since in most legislations you need to be a resident in order to be eligible for a geographical number and so it's legally impossible to set up a service with numbers from all these countries. From my experience that's at least the case for Germany, France and Italy (which does not mean that you can't get a number from these countries
).
So you will have to sign up for a service in each of these countries. Sipgate.de verifies customer's identity through a credit investigation company called "Schufa", so you would need a German resident whose name, address and date of birth you can use during registration. Once you find a German resident I could guide you through the registration process.
For Italy there's
Messagenet - VoIP - Telefonare con Internet who assign free Italian geographical numbers but you'll need to provide a valid Italian address (which will not be verified) and a "Codice fiscale" (which you can generate
here).
French numbers can be obtained from ippi.fr who also require a valid French address but do not verify your personal details.
As of Turkey and Poland I have never registered for a VoIP service in these countries.
If you need Austrian and Swiss numbers:
Free local Swiss numbers are available from sipcall.ch while sipgate.at offer Austrian numbers in the 0720-range which is billed very inconsistently among the different operators (some charge call to those 0720-numbers like landline calls, others as premium numbers) but fortunately there's a Vienna-based company running an ENUM-gateway through which all sipgate.at numbers can be reached at the cost of a landline call by adding the prefix 01326 and omiting the 0 from the 0720 prefix. So instead of dialing 072012345678 callers need to call 0132672012345678 and the call is billed like a landline call.
Good softphones support mulitple SIP accounts, so you can use them all simultaneously. For best VoIP experience get a AVM Fritz!Box which is a family of ADSL routers with integrated PBX and ATA adaptor with countless functions. The Fritz!Box supports up to 10 VoIP accounts which you can use by standard analogue phones connected to the box (newer models even have a DECT base station for cordless phones integrated).