
sk8r_dan_man |

Does the bonus unarmed damage from the robes stack with that of the feat?
Aura moderate transmutation; CL 10th
Slot body; Price 13,000 gp; Weight 1 lb.
Description
This simple brown robe, when worn, confers great ability in unarmed combat. If the wearer has levels in monk, her AC and unarmed damage is treated as a monk of five levels higher. If donned by a character with the Stunning Fist feat, the robe lets her make one additional stunning attack per day. If the character is not a monk, she gains the AC and unarmed damage of a 5th-level monk (although she does not add her Wisdom bonus to her AC). This AC bonus functions just like the monk's AC bonus.
Construction
Requirements Craft Wondrous Item, righteous might or transformation; Cost 6,500 gp
Your formal unarmed training continues to bolster your training in other areas.
Prerequisites: Still mind class feature, Improved Unarmed Strike.
Benefit: Add half the levels you have in classes other than monk to your monk level to determine your effective monk level for your base unarmed strike damage. This feat does not make levels in classes other than monk count toward any other monk class features.
For example, if I had a 3rd level monk/8th level other, could I gain 4 effective monk levels for unarmed damage from the Monastic Legacy Feat, and then wear Monk's Robes for an additional 5 levels, and deal the unarmed damage of a 12th level monk? (3+5+8/2=12)

mplindustries |

For example, if I had a 3rd level monk/8th level other, could I gain 4 effective monk levels for unarmed damage from the Monastic Legacy Feat, and then wear Monk's Robes for an additional 5 levels, and deal the unarmed damage of a 12th level monk? (3+5+8/2=12)
Yeah, I don't see any reason why that wouldn't work.
I wouldn't waste so many resources on getting better unarmed damage dice, though. The base weapon dice are the smallest source of damage for 95% of all damage dealers-static mods are where it's at.

Dabbler |

For example, if I had a 3rd level monk/8th level other, could I gain 4 effective monk levels for unarmed damage from the Monastic Legacy Feat, and then wear Monk's Robes for an additional 5 levels, and deal the unarmed damage of a 12th level monk? (3+5+8/2=12)
Spot on. As mplindustries says, though, the real damage boosts are in threat range and static damage bonuses, so if your choice is between Monastic Legacy and Improved Critical, go for the latter.

Kazaan |
But, going back to the question at hand, Monk Robes counts your Monk level 5 higher to determine Unarmed Dice, Monk AC, and Stunning Fist DC while Monastic Legacy adds half your non-Monk levels to your effective Monk level for Unarmed Dice only. Furthermore, they're both "untyped" bonuses to effective Monk level so, even if both added "in the same way", I don't see any reason why they wouldn't stack.