I think, not sure because I don't have it on my monk, Mruuk's Combat Boka which is a 1 hand blunt has yellow 7s coming out of it. You can buy it, but it's expensive ranging from 800 platinum to 1300 platinum.
These are the items I have on my monk alt. Just starting off the cheapest item you could get would be Yaralith's Fist.
Yaralith's Fist - Drops in Hidden Temple of Yaralith, red flashy fist
MAGIC ITEM LORE ITEM
Slot: PRIMARY SECONDARY
Skill: Hand to Hand Atk Delay: 25
DMG: 9
Effect: Choke
Recommended level of 20
WT: 1.2 Size: SMALL
Class: MNK BST
Race: ALL
Ugahn's Severed Claw - Not sure where it drops, sparkly blue,white claw
MAGIC ITEM LORE ITEM
Slot: PRIMARY SECONDARY
Skill: Hand to Hand Atk Delay: 29
DMG: 15
Dex: +6 STA: +4 AGI: +4
Recommended level of 25
WT: 0.1 Size: SMALL
Class: MNK BST
Race: ALL
Fanged Fist of the Kedge - Drops in Kedge somewhere, red flashy fist
MAGIC ITEM LORE ITEM
Slot: PRIMARY SECONDARY
Skill: Hand to Hand Atk Delay: 29
DMG: 14 AC: 6
Cold DMG: 2
Effect: Choke (Combat)
STR: +5 WIS: +5 HP: +30
Recommended level of 36
WT: 0.3 Size: TINY
Class: MNK BST
Race: ALL
As for a droppable robe useable monk item, not sure on this either, but I believe Mummy Wrappings is a robe item because the little picture looks like a blue robe from what I've seen.. If someone else could confirm that'd be nice. I've seen Mummy Wrappings on listsold for 600-800 platinum.
Mummy Wrappings
MAGIC LORE
Hp: +25
Mana: +25
Str: +5
Sta: +7
Sv Disease: +20
Sv Poison: +20
Weight: 0.8
Ac: 21
Size: Small
Slot: CHEST
Race List: HUM ERU HIE DEF GNM IKS FRG
Class List: WAR PAL RNG SHD MNK BRD ROG BST
Another possible monk robe would be Gown of Gloomwater, can't confirm it's a robe myself because I don't have this either. Not much in to robes for my monk, have Rejuvenating Hide and Grandmaster's Chestwraps of the Risen for later. Hmm, just noticed the wiki doesn't list the AC on the Gloomwater, getting AC from Shards of Dalaya Resourcarama.
Gown of Gloomwater - According to the wiki this drops from the Lady of the Deep in Siren's Grotto
MAGIC ITEM LORE ITEM
Slot: CHEST
Effect: Recovery V (Worn)
WIS: +15
SV COLD: +10
WT: 0.2 Size: LARGE
Ac: 22
Class: CLR MNK
Race: HUM ERU HIE DEF GNM IKS FRG
Augment Info: Slot 1, Type 5