Recovering a Caster Level

[Vhaidara]

So, I am applying to a PbP where we all start as level 1 wizards at a wizard college. We cannot lose more than 3 wizard caster levels (must reach 9ths by 20) or we flunk out.

My plan is to go with an Int 11 half giant. Original plan was Wizard 5/Full BAB 2/Eldritch Knight 10/Wizard or full casting PrC 3.

GM mentioned the possibility of Siege Mage. As a Half Giant, I can wield a cannon as a 2 handed firearm, meaning the ideal option is Siege Mage Wizard 5/Musket Master Gunsligner/Eldtrich Knight 10/Wizard 2. Musket Master lets me reload the 2 handed firearm at one handed speed, so I can attack every round instead of every 3 rounds.

The problem is that I now lose 4 caster levels (3 gunslinger and 1 EK). Is there a way to recover my lost caster level? Maybe a third party PrC like EK that doesn't drop a CL at 1?

[Segev]

White Dragonspawn, from the Dragonlance setting, gives +1 sorcerer level. That's not a wizard level, though.

Would Practiced Spellcaster's level-boost count?

[Vhaidara]

White Dragonspawn, from the Dragonlance setting, gives +1 sorcerer level. That's not a wizard level, though.

Would Practiced Spellcaster's level-boost count?

First, pathfinder, not 3.5 And I need to actually get another level of casting out of it.

[Segev]

See if you can talk your DM into a variant on the Monk's Robe (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/r-z/robe-monk-s) that instead is a Gritty Duster. Takes the same body slot, but gives a +4 bonus to your Gunslinger level for purposes of Grit and Deeds. Then take only 1 level of Gunslinger, relying on your duster to get you the 3rd-level Deeds.

[Psyren]

Find some way to keep Reloading Hands (http://www.d20pfsrd.com/magic/all-spells/r/reloading-hands) active on your cannon.

[Kraken]

How about hellknight enforcer (http://www.d20pfsrd.com/classes/prestige-classes/other-paizo/e-h/hellknight-signifer) instead of EK? It's only medium BAB, but it gets decent class abilities.