Getting a domain without taking a level in cleric?

[Zanos]

Anyone know of anyway to do this? I'm looking to make an arcane Dweomerkeeper, which requires the magic domain, but would prefer not to have to take a cleric level.

[Chronos]

A number of the prestige classes in Complete Divine, some of them arcane-eligible, grant domains, but they're mostly specific domains, and I don't think any of them is the magic domain.

[AmberVael]

Well, assuming you can count your spells as divine spells somehow (which you'd need to get Dweomerkeeper anyhow), you could use two levels in the Singer of Concordance prestige class. Races of the Dragon, page 91.
It requires divine casting to enter, but can advance any casting class, and gets the Magic Domain (or a different domain) as a bonus domain at its 2nd level.

[ben-zayb]

Contemplative gives up to two domains, and there are feats/PrC to make arcane spellcasting count as divine

[Âmesang]

Divine Emissary grants a domain… but it's also an epic prestige class.

…though it leaves me wondering if a paladin/blackguard prestiging into it and taking Improved Spell Capacity 5th-9th would gain access to the domain's 5th-9th level spells (even if only once per day each)?