Sometimes it is necessary to install some packages to the host, that has no Internet access. In that cases the only way is to make a direct port forwarding, then ssh to forwarded port and make a reverse port forwarding, pointing to an external HTTP proxy.
AFAIK there is an HTTP proxy implementation in ServerAccess. So it might be possible to create a reverse port forwarding to a local proxy with a single button.
It's interesting idea. But you know, HTTP Proxy branch is not merged to master yet (and it is not well done yet). Since that, this feature will be implemented not very soon.
Sometimes it is necessary to install some packages to the host, that has no Internet access. In that cases the only way is to make a direct port forwarding, then ssh to forwarded port and make a reverse port forwarding, pointing to an external HTTP proxy. AFAIK there is an HTTP proxy implementation in ServerAccess. So it might be possible to create a reverse port forwarding to a local proxy with a single button.