A guy at work used to use a cloud service called Shadow PC.

They'd basically rent a gaming PC out and he'd just torrent them right on to the cloud machine. Pretty sure mods would have worked there.

It felt a touch laggy with a mouse, but a controller would probably have been just fine. It's a shame there's a disconnect between what gamers want (a gaming PC that's just somewhere else) and what providers want (a walled garden).