Does anyone know if it is possible to setup a WCF service running on IIS 7.5 so it would start automatically (and not waiting for the first request to come in), without the installation of AppFabric?
You can achieve this by using the module IIS 8.0 Application Initialization, which is compatible with IIS 7.5:
IIS 8.0 Application Initialization
Here's the download link for IIS 7.5: Application Initialization Module for IIS 7.5
An alternative would be to write a small app which calls your service, you could then schedule that to run regularly or when your app pool is recycled.