There is, it's called downsampling. You can add a custom resolution that is higher than your native one and your monitor will scale down, providing OGSSAA basically. I have a 1280x1024 monitor and I play in 2560x2048@1280x1024. Also works great with screenshots. Here is a nice comparison between native 1080p and 3840x216@1080p:
This is possible via driver only with a Nvidia graphics card (every API, but only Win7) and via the SSAA tool from tommti (only DX10/11), although the tool can be buggy, doesn't alyways work and is no longer being improved/supported.
Current drivers are a bit lacking. Before it was often possible to achieve 3840x2160@57Hz (never at 60, though) with certain monitors. Nvidia knows that the enthusiast community appreciates downsampling and said it will get better in a future driver branch. It was messed up unintentionally in 280.x drivers. Also, there is the possibility that they will provide native support for that, because currently it is quite tricky and not always successful, because it all depends on the monitor as of now.
btw, GTA 4 is perfect for downsampling (either via driver or mod). Ever heard of ENB series? You can play GTA 4 in up to 4x (or 16x, depending on how you look at it) the native resolution, having 4x4 OGSSAA. Extremely demanding, though. I can barely play it in 3840x3072 with a overclocked GTX580 3GB SLI.