I was looking for a lightweight stock for my Tikka T3 lite as well. This is what I found a couple of months ago:
MPI can install a featherweight style stock on your Tikka T3, or Lone Wolf can also install a Summit stock on your Tikka T3. I believe McMillan may come out with an Edge style hunting stock for the Tikka T3 around this summer. Then again, Manners has the MCS-T4 available now. Manners' MCS-SL (i.e. super light) may be available by May of this year.