couple of people have mentioned this to me (on this board i think) and suggested the nuts were so tight thatthey snapped a breaker bar trying to get the thing undone i have not found mine to that tight
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.
There are a couple of points here, the strength issue mentioned by Shazaam is the reason certain areas of the bike (brakes mainly) are included in the ACU Handbook where it is classed as unsafe to use Titanium fittings and is therefore against the rules. Then there is the point of Production costs which is often the reason why less exspensive materials are used although more exotic materials would work just as well. I have always taken note of the ACU ruling on Titanium fittings and use it as a guide. For that matter I have had a alloy rear wheel nut on my 998 for the past 6 months without any problems.