I-beam cursor color in Mavericks's terminal
As many have mentioned above, I did this - 


Take a backup of existing ShadowedIBeam.tiff

cp Terminal.app/Contents/Resources/ShadowedIBeam.tiff Terminal.app/Contents/Resources/ShadowedIBeam.orig.tiff

Make your own cursor .... or, if you are a lazy one, just use this one -  (credit: Chris Dragon and his answer on this thread)
Then copy it over the original ShadowedIBeam.tiff

sudo cp ~/Downloads/TIbeam.tiff Terminal.app/Contents/Resources/ShadowedIBeam.tiff

And finally, run this - 

defaults write com.apple.Terminal UseCustomIBeamCursor -bool YES



If you were as lucky as I was, you should have your eyes profusely thanking you in sheer gratitude!