Consider the following scenario: There is a client behind a really strict firewall. There is nearly nothing available to 'connect to the internet'. Just DNS resolution and HTTP/HTTPS (some whitelisted sites like Google can be visited; others get redirected to the 'site was blocked' page).

So the idea was to to build some kind of proxy using only http get requests (using this service from google as proxy which works fine but lacks css/http post request support)

Do you think that's possible or are aware of software that's capable of doing this? Or maybe another way to accomplish unrestricted internet access under these cirumstances?