Crafting in Vagrant Story offers so many combinations, there is not room to place all of them on one page, and with the exception of shields, not even room to place a single category on one page. Below are the pages of all the combinations possible with single armor Equipments.
There is no word in the English language for "piece of armor at a particular location on the body", so for the sake of this guide, the awkward but functional word 'Equipment' is used, as in, "Segmentata and Brigandine are both equipped on the Body Armor Location, and are therefore both Equipments of the Body Armor type".
As with weapon combinations, armor has a succession of Tiers of progressively greater power. Combining adjacent Tiers will produce a yet higher result, until the highest Tiers, when a Tier must be combined with itself to progress, and the highest Tier will always produce the same Tier when combined with itself.
Combining two different Equipments will usually result in a lower Tier version of the highest-Tiered of the two ingredients. If the two Equipments are close or the same in Tier, however, there may be a Morph to a third Equipment type, which is useful when trying to make use of a surplus of a certain Equipment type.
Mismatch is a tendency in weapon combination, but a rule with armor; there is a direct correlation between how far away the Tiers of combined pieces are and how high the Tier of the result is, but not the correlation one might expect, namely that the closer they are, the higher the Tier. In fact, it is the opposite; there is a heavier penalty on combinations that are close together but not consecutive, than there is for combining a very low armor with a high one. It can be seen when the highest Tier body armor, the Dread Armor, is combined with other body armors; the higher the Tier of the body armor combined with it, the lower the Tier of the results.
Weapon & Armor Combinations (Vagrant Story) - geocities cached page