Sorry if this has been covered earlier; I didn't go back to read the whole thread. Do your schools have a gifted coordinator (even if the program doesn't start until later)? If yes, I highly recommend contacting that person and asking for help/advice. GCs should be good at differentiation and hopefully can offer assistance to the teacher to provide more appropriate work. The GC may also be able to help get the ball rolling on testing.
Other things we did in kindy-- we sent in books at our kiddo's level. Since DS's math ability was easiest to show, we asked after they tested him if they would allow him to do his math online when the others were learning basic stuff (EPGY or Aleks). They were willing to explore this, and eventually the GC came up with a plan to compact the 2d grade math curriculum and teach DS during pullouts.
I know that not all schools will be as flexible as mine was that year, but when you kindergartner doesn't want to go to school, and cries everyday (well, mine did), it is not normal and it's worth trying to fix.
