I'm on the same quest for "Brutus," my '72 F-250 2WD Camper Special. In looking through this forum again today, I found another thread asking the same question to which Fordmando posted a reply on 10/8/04 suggesting www.inlinetube.com. I went racing over to that site and naturally they don't list my truck. I didn't see a specific listing for a '93 F-350, but you might check to see.
It looks like the cost of a complete set of brake lines for my application would have been about $185 (plus S/H, I think), a little too steep for me. I thought I'd pass the info along anyway. Thanks Fordmando for the potential source!