Development of the R package tikzDevice has been underway for about a month now. This package allows for the output of R graphics as TikZ commands.
Charlie Sharpsteen and I have gotten it into an alpha stage. There is no real documentation but there is plenty of comments in the code. We have a R-forge project where binary packages can be downloaded. The project is also tracked by Github here or at my fork.
As of now the device handles most of the graphics parameters. There are still some issues with text placement and UTF8 string support is currently not implemented.
Comments, suggestions are welcome.