There was a Japanese gentleman selling Titanium rods on Ebay
He also has rods made for upright bass
I am not sure but I think 10mm is a little small for Double Bass
Mine have 12mm
If you need his address please email me
I have heard because it is lighter that the sound could be a little brighter and more clear for pizz than steel. At the moment I have the KC Strings wood/carbon rod which is lighter than steel and makes my bass louder but more diffuse than the steel rod. We'll see what happens with the titanium.