Using Proxy Server to act as hosts file
Solution 1:
Fiddler can do this. Using custom rules in it's CustomRules.js file, you can simulate the Windows hosts file by pointing one hostname to a different IP address. An example is provided on their script samples page:
// All requests for subdomain.example.com should be directed to the development server at 128.123.133.123
if (oSession.HostNameIs("subdomain.example.com"))
{
oSession.bypassGateway = true; // Prevent this request from going through an upstream proxy
oSession["x-overrideHost"] = "128.123.133.123"; // DNS name or IP address of target server
}