Why not an off-the rack steel bike? I know nothing about DeSalvo, but they don't seem to really have "custom" sizes. They have a range of sizes just like any other manufacturer. A lack of tall sizes like that would disappoint me. My best fitting bike is 66cm CTT, and nothing on their site would fit me.
My Jamis Satellite is a featherweight, and even as a big rider who puts down some good wattage, it's not noodly or flexy, but then I have no real experience on AL TI or C so YMMV.
__________________
The bicycle, the bicycle surely, should always be the vehicle of novelists and poets. Christopher Morley