In that case, Red Wizard or Hathran powers reserve feats better than almost anything, Heighten your reserve spell through Circle Magic to level 20 and enjoy the spell level benefits.
Seems kinda lame to get Circle Magic for this, though. It's like using a nuclear bomb to kill a rat.
Just looked up the Reserve Mage. I'm not sure Circle Magic would work, the way this is written:
http://www.giantitp.com/forums/showthread.php?t=147086I know, arguing the RAW of a homebrew class... Still, there are some other things to bring up:
1) Reserve mage is 3/5. Get a couple of caster levels from the other side to fill in the lost levels. Also, consider skipping the capstone. I'm not confident it's worth another lost caster level.
2) With antifeats, there's no reason at all to take Wizard past 5. With Reserve Mage, there's little reason to take it past 3, although you'll want to take a 4th level on the opposing side to maintain full casting as a Wizard, and +1 CL/+1 Feat is tough to beat for a single level.
3) 7 Reserve feats: Aquatic Breath, Dimensional Jaunt, Dimensional Reach, Minor Shapeshift, Sickening Grasp, Summon Elemental, Sunlight Eyes. Don't take any others, especially the Damage ones. That's what your EB is for.
A better level progression:
First level: Wizard/Factotum
Next 2 levels: Wizard/Warlock
Next level: Binder/Wizard
Next level: Reserve Mage/Wizard
Next level: Reserve Mage/Warlock
Next 2 levels: Eldritch Theurge/Factotum
Last 12 levels, any order (match the Binder level with a Reserve Mage level): Reserve Mage 2/Anima Mage 10 | Binder 1/Warlock 11
Finished setup: Wizard 3/Binder 1/Reserve Mage 4/Eldritch Theurge 2/Anima Mage 10 | Factotum 3/Wizard 2/Binder 1/Warlock 14
Wizard CL 20 (full casting), Warlock Level 16 (EB 7d6, 1 Dark Invocation), EBL 14 (2 Vestiges, 6th-level max)
EDIT: My bad, fudged the math a little.
In any case, Factotum is way better than anything you get from Swordsage, especially with Antifeats to get all the FoI's you could ever wish for. Spellfire Wielder is not good, you're going to find yourself just using your other abilities. Don't bother with Martial Study for IHS, just use a 3k Iron Heart Vest from the same book to get it. Even though you have so many, it's still better than 2 feats.
EDIT 2: As for what to do with all those open feats... Font of Inspiration. Also, do NOT take Unreactive. The worst flaw in the game. Inattentive is better, Noncombatant isn't bad, Fussy is godly. Other good feats to pick up: Spell Focus (Divination), Insightful Divination, Improved Initiative, Uncanny Forethought, Divine Denial... I'll make a list and show it to you, later.