135 f/2.0 with IS would be awesome ... if they do release it, I hope Canon goes easy on its pricing.
Your hopes will be dashed!! It will double in price from the current version, for sure.
I agree with DS... "If" Canon produces a 135mm f/1.8 with IS it will have a hefty price based on their current upgrade pricing policies... I think a 135mm f/2 IS is more realistic and even that will carry a heavy price for admittance. No doubt! I do not own the current 135mm, but most photographers wax poetic about its abilities...so if an update is made I would expect conservative Canon to make it an incremental update, nothing big and splashy....but ya never know.
5D Mark III, Canon 15mm f/2.8 Fisheye, Canon 17mm f/4L TS-E, Canon 16-35mm f/4L IS, 21mm f/2.8 Zeiss, Sigma 35mm f/1.4, 24-70mm f/2.8 II, 50mm f/1.4 Sigma Art, 85mm f/1.2L, 100mm f/2.8L Macro,70-200mm f/2.8L IS II...1.4x converter III, and some other stuff.....