| Ducati Performance do sell Titanium wheel nuts, would not like to hazard a guess at the sort of price they charge though. A pair sold on ebay last week for £73 plus postage.
I find that my Standard wheel nut tightens itself while the sprocket side slackens itself. Need to check and re-torque both every 1000 miles else sprocket is finger tight and wheel side virtually impossible to remove.
You might want to check out what pro bolt say about titanium fastenings. Would not think that they would be keen on the statement that replacement of steel with titanium is not the way to proceed. | 
916Neil
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