I imagine you'd not even bother addressing Arcane Swordsage, seeing as it's rather silly in general, but Arcane SS 5 is a great entry. I'm pretty sure maneuver progression interaction results in you getting .5 initiator level from the no-progression levels of the PrC, while those levels that do progress progress your spell/maneuver stuff... Meaning you still get access to ninth level spells/maneuvers, at level 19.
Plus, y'know, have no trouble keeping that Haste active every fight, along with whatever other buffs you choose.
That would be a really nice entry. Let's consider an Arcane Swordsage 5 / Swiftblade 10 / Abjurant Champion 5.
Spells by level (Evocation/Transmutation/Abjuration):2nd - Wraithstrike, Heroics, Glitterdust
3rd - Haste, Dragonskin, Repelling Shield
4th - Mirror Image (Greater)
5th - Dimension Door (Greater) , Lightning Leap, Telekinesis
6th - Antimagic Field, Ruby Ray of Reversal, Contingency
7th - Synostodweomer, Energy Absorption
8th - Mystic Shield, Celerity (Greater), Ghostform
9th - Replicate Casting, Absorption, Dragonshape
Runestaff:Magic Weapon (Greater)
Heart of Water
Heart of Earth
Luminous Armor (Greater)
Elemental Body