First of al those truck design look awesome - nice work
as for the price of the titanium
. . . . the first set of titanium axles i got came from spike at Design Extreme when he was still manufacturing them and cost me 150 pounds
i purchased a second set from a friend for one of my other decks for 50 pounds which was about the cost of the raw materials
titanium is a very soft alloy ( the nylon in the revos does flat spot the axles a bit it over time )
it is very easy to machine the problem arises when you want to weld it this has to be done in a zero oxygen environment (argon i think from memory but not sure)
one of my good friends was lucky enough to have some made (as a gift ) out of some really exotic titanium (as its an alloy there is many variations and prices) How they got around the welding was to machine a very shallow groove in the middle of the axle enabling them to use two stainless steel half rings and weld them to each other with the groove keeping it in place
Titanium is actually slightly less strong than stainless steel so don't skimp on the axle thickness. . .
i have a few different revo setups and three different styles of axle in stainless and Ti if anyone wants any pictures or dimensions i am happy to help