Play a high-level Shaper psion, 16th-level or higher (it's an 8th-level power), and use the True Creation power. Permanent, nonmagical, nonpsionic, completely normal items and materials are created, but it costs you 10 XP per 1 GP of value (at least in 3.0, dunno if it changed in 3.5). Probably best to use gradually over time (i.e. create a single plate for a suit of mithral full plate, hunt down a few slightly-tough monsters for XP, repeat until all pieces are made, then create the portions of mithral chainmail that bind the pieces together, and the suit of padding that goes within).