There is also thistledown padding from Races of the Wild; for 500gp, it can be added to any metal armor and reduces ASF by 5%. And there is also Feycraft armor, a template from the DMG II that can be added to medium and light armors (up to mithral fulplate) that reduces it by another 5%.
So you could have a suit of twilight feycraft mithral fullplate +1 with thistledown padding with an ASF of 5% total.