Unfortunately I cannot afford any time on other people's projects at the moment (my PhD defense is coming soon), but you can go ahead and make it pass R CMD check first. Charlie (author of tikzDevice) once told me the tricky part was the tests; there are some graphical tests using ImageMagick, and all the tests may take a while to finish.

I have been asked many times how to install tikzDevice, and I really hope it can go back to CRAN. If you can contribute some time on it, I'll be very excited and will be happy to join you after my defense.