Nordic Hardware claims Blizzard and Valve may be working with ATI on broader DirectX 10.1 support:
If AMD has played its cards right, Blizzard is not only looking to implement DX10.1 support, and in best-AMD-case scenario, DX10.1-exclusive effects, with future games, but also patch current games with DX10.1 for additional performance and effects. If everything comes together for AMD, this means that StarCraft 2, Diablo 3, future World of WarCraft add-ons, and more games from Blizzard will sport DX10.1, something which NVIDIA is unable to handle hardware-wise.
That's not all though. We recently learned that AMD is looking to team up with more developers, and if there's one engine that has loved ATI hardware for a long time, it's the Valve Source engine. ATI is apparently hoping to ensnare Valve as well, and have DX10.1 support with future games like Half-Life 2: Episode 3, Left 4 Dead, Portal 2 and the rest. Knowing how flexible the Source engine is, we wouldn't be surprised if current games would be patched to further boost performance and additional effects through DX10.1.