Serrated Dirk -> Manamune?
Manamune
Recipe: Serrated Dirk (1100) + Tear of the Goddess (750) + 550 = 2400
+25 Attack Damage +250 Mana +50% Base Mana Regen
Unique Passive: +10 Armor Penetration
Unique Passive - Awe: Grants (2% Maximum Mana) bonus Attack Damage
Unique Passive - Mana Charge: Grants +4 Maximum Mana for each basic attack, spell cast, or other Mana expenditure, up to twice per 8 seconds. At 750 Mana gained this way, this passive is lost and this item transforms into Muramana.
Muramana
+25 Attack Damage +1000 Mana +50% Base Mana Regen +10 Armor Penetration
Unique Passive - Awe: Grants (2% Maximum Mana) bonus Attack Damage
Unique Toggle: Single-target spells and basic attacks (on-hit) consume 3% of your Current Mana to deal twice that amount as bonus Physical Damage.
Increase the BMR by 25% (the fact that the BMR doesn't increase on it from Tear always struck me as odd), and build it from a Serrated Dirk so it grants ArPen. Virtually every consistent Manamune user likes or doesn't mind ArPen anyway, so I figured why not. Plus Dirk could use another thing to build into.
(Would it granting ArPen mean that Talon would consider buying it? I don't play Talon, but he does like raw AD and wouldn't mind the extra mana. He probably can't charge it that easily, and doesn't really want to be rushing a Tear, so maybe not...)