Adapter for moving bottle cage up/down while using frame's bottle cage braze-ons Are there adapters available for moving a bottle cage up/down in the frame? I am trying to move my seat tube's bottle cage down 4-5 centimeters and I prefer using the braze-ons.

Note: the question is about options using the frame's braze-ons, not external adapters.
There are a number of commercial products available to move bottle cages up or down from the existing braze-ons. They're marketed as a Bottle Cage Relocator or Bottle Cage Adapter, but essentially they're all a flat piece of metal with holes drilled into it that may have some finishing work to make it look nicer. Given they're in the $10 range it's probably a better use of your time to buy one than DIY.