I just tried winetricks dotnet11 in wine-1.5.5-262-g31907e0 and it seemed to install successfully. Whether it's usable, I don't know, as I don't have a .NET 1.1 app to test, but there were no "Failed to load resource file" messages and no crash. I do have wine-mono installed, and did not uninstall it before running winetricks.