Regarding the recent R discussion, this came across the R users list today. The author has put together some scripts that interacts with the console version of R via vim. He's reported that it doesn't yet work on OS X, but perhaps his code may be useful for working out some of the problems/goals that people have been raising with TextMate/R.
http://www.uft.uni-bremen.de/chemie/ranke/index.php?page=vim_R_linux
Cheers- -Alan