@SpiderDice Check under the frame too. I found two bolts under the lower frame rail which should allow for a water bottle bracket as well. I would be worried about a bracket mounted at the spot in your photo interfering with steering control and posing a safety issue.
I ordered the Problem Solver Bottle Cage Height Adapter, $10, from Universal Cycles. I was worried the bottle cage might pinch the cable. The height adapter has plenty of room for the cable to run behind it and allows me to adjust the cage height up/down for best placement of my 25 oz Camelbak water bottle.
I also just switched to Arundel Looney Bin Cage, $25, amazon (available in black or white). It can adjust it size to fit small to large containers like small 12 oz water bottle to large 32 oz Gatorade bottles.