Ever getting more than 1 familiar?

[AlienFromBeyond]

It seems generally clear to me that taking multiple classes that give a familiar simply stacks them for the stats of the familiar, but there are a couple of other methods that can get you one at the same time as your class. For instance, if I'm an Eldritch Guardian Fighter and take Eldritch Heritage (Arcane) and have a Variant Multiclass in Wizard, how many familiars do I get and at what effective wizard level?

[grarrrg]

It seems generally clear to me that taking multiple classes that give a familiar simply stacks them for the stats of the familiar, but there are a couple of other methods that can get you one at the same time as your class. For instance, if I'm an Eldritch Guardian Fighter and take Eldritch Heritage (Arcane) and have a Variant Multiclass in Wizard, how many familiars do I get and at what effective wizard level?

1 Familiar only, ever.
The only exception would be if something specifically said "you can have an extra Familiar" (I am not aware of anything that actually has this ruling).

As for effective level, the only official thing we have to go by is:
"Levels of different classes that are entitled to familiars stack for the purpose of determining any familiar abilities that depend on the master's level."
As is typical of these types of things, the ruling was written WAY back at the beginning, where it was nigh-impossible to have 2 Familiar progressions at the same time, and they haven't ever bothered to go back and revise/clarify anything.

Thus, the RAW ruling is "add them all together", so you'd have ~3 times your level worth of Familiar progression with your proposed build.
The catch is that Familiars scale off of two different things, your base stats, and your 'effective Wizard level'. There's no real way to boost your base stats outside of gaining levels, and 'effective Wizard level' gives no bonuses after level 20, and the bonuses it does give aren't really game-breaking. So despite "super fast Familiar progression", this isn't really seen as all that broken or cheesy.

The RAI ruling is probably "caps at your character level".
You'd have to check with your DM which version they would let you run with.

[Coidzor]

There's the spell Duplicate Familiar (http://archivesofnethys.com/SpellDisplay.aspx?ItemName=Duplicate%20Familiar). So a custom item of that with a continuous duration would let you have an additional familiar per item, I think.

Trompe L'oeil (www.d20pfsrd.com/bestiary/monster-listings/templates/trompe-l-oeil-cr-1) creatures made of your familiar would have your familiar's special qualities and abilities, so theoretically they'd also be linked to you as familiars.

[Mordaedil]

The only way to get more than one familiar is with the express approval of your DM.

There is a precedent for it however, the cover of Complete Mage features a wizard with two rats for familiars.

Personally I don't see it as particular problematic as long as there are a handful of restrictions in place: You can only benefit from the skillpoint bonus or whatever from one of your familiars. It dies and you've lost that bonus. You can also only control and cast spells from one familiar at a time. They must "touch back" to transfer to the other familiar.

You may still use both to scout, but you can only receive perception from one familiar at a time.

[Bronk]

There's an 'extra familiar' feat in 3.5, maybe you could port that over to Pathfinder?

[Ruethgar]

Of course even within 3.5 Extra Familiar needs DM adjudication for its lack of rules such as what classes advance it at what rate. Also note that it has no prerequisites like Obtain Familiar so a Fighter could get one if the really wanted.

[Vizzerdrix]

Of course even within 3.5 Extra Familiar needs DM adjudication for its lack of rules such as what classes advance it at what rate. Also note that it has no prerequisites like Obtain Familiar so a Fighter could get one if the really wanted.

Would that be such a bad thing?

[Ruethgar]

Would that be such a bad thing?

Not at all, just saying it might need some extra work and some DMs might find it unusual and thematically inappropriate that a mundane can perform a magical ritual(though there is at least one magic fighter ACF set in 3.5).