If you are looking for some sort of progression for your shadowknight, let me name off a few knight specific weapons he can use which you can look for. You can start off with a High Knight's Vengence from level one, as for blunt and piercing I'd go with mithril till you get to the recommended level of the upper knight weapons. Two hand blunt and two hand slash is iffy, so I'd go Mithril till you can find a really good two hander for each. There aren't many knight specific two hand weapons for the lower shadowknights.
High Knight's Vengence - (no level requirement, should proc from level 1)
Zone: Temple of Yaralith
Mob: High Knight Yan`Vzia
MAGIC ITEM LORE ITEM
Slot: PRIMARY
Skill: 1H Slashing Atk Delay: 24
DMG: 11
Effect: Drowsy (Combat)
WT: 4.0 Size: MEDIUM
Class: PAL SHD
Race: ALL
Lava Infused Morning Star - (Not sure where this one comes from or recommended, but I've seen it in game.)
Dmg: 12
Atk Delay: 21
Agi: +5
Wis: +5
Intel: +5
Sv Fire: +7
Skill: 1H Blunt
Weight: 2.7
Size: Small
Slot: PRIMARY
Class List: PAL SHD
Race List: ALL
Effect: Mana Conservation II
Blade of Spiritual Infusion - (Recommended level of 26, going off Wiki for this one because don't have it)
Zone: Lair of Paw
Mob: The Mind Claw
MAGIC ITEM LORE ITEM
Slot: PRIMARY
Skill: 1H Slash Atk Delay: 24
DMG: 15
Poison DMG: 3
STR: +4 AGI: +4 WIS: +4
WT: 5.5 Size: LARGE
Class: PAL SHD
Race: ALL
Spear of Savagery - (Recommended Level of 28)
Zone: Keep of Mielech
Mob: High Templar Ftirgir
Slot: PRIMARY
Skill: Piercing Atk Delay: 18
DMG: 13
Effect:Tearing Blow (Combat)
WT: 3.0 Size: MEDIUM
Class: PAL SHD
Race: ALL
Cryptic Runed Flail - (Recommended level of 42)
Zone: Mielech's Lair
Mob: a froglok mummy
Cryptic Runed Flail
MAGIC ITEM LORE ITEM
PRIMARY
Skill: 1H Blunt Atk Delay: 23
DMG: 18 Effect: Jinx (Combat)
Required Level of 30.
WT: 5.5 Size: SMALL
Class: PAL SHD
Race: ALL
Malignant War Mace - (Don't know recommended level, but sure it's above Cryptic Runed Flail)
Zone: Eldenal's Mansion
Mob: Lady Lianna
PRIMARY
Skill: 1H Blunt Atk Delay: 25
DMG: 23 Effect: Curse of the Simple Mind (Combat)
DEX: +11 STA: +11 AGI: +8 HP: +20
WT: 12.0 Size: LARGE
Class: SHD
Race: ALL
Revenant's Blade - (Recommended level of 50, and a great alternative to Rotblade)
Slot: PRIMARY
Skill: 1H Slash Atk Delay: 20
DMG: 17
Effect: Yaulp III (Combat)
Focus Effect: Damage Increment II
STR: +10 DEX: +4 AGI: +4
WT: 1.7 Size: MEDIUM
Class: PAL SHD
Race: ALL
Obsidian Tower Shield - (Great shield to pair these weapons up with)
http://www.angrygamer.net/sodwiki/index.php?title=Bloggo%27s_Shield
Slot: SECONDARY
AC: 23
STR: +4 WIS: +4 INT: +4 HP: +30
WT: 10.0 Size: LARGE
Class: WAR CLR PAL RNG SHD BRD ROG
Race: ALL