Could a wizard turn himself into a WCV?

[Tedronai]

If you're asking if it's canon and consistent of what we know of White Court Vampires in the Dresdenverse, no.

If you're asking whether your GM could allow you to do it, sure, why not ... a GM can theoretically allow you to be part man, part aircraft carrier if he or she so chooses.

Some of you may disagree with me, but I'm pretty damn certain that the 'demon' part of being a WCV isn't actually literal as it is a personification of the Hunger. There's no Demonic Co-Pilot attached to the WCV template and even Harry's use of the sight is highly laden in imagery and metaphor. The one thing we do know for certain is that White Court Vampires are born that way and either turn in their teens when they give it to their hunger, or find True Love/Hope/Courage/whatever and become human. There hasn't been a single example in the books of WCV that did not inherit it from birth.

While it's certainly not established in canon as a possibility, it's also not at all established as NOT a possibility, and there is at least some evidence to suggest that it might be (references to the Hunger as a separate entity bonded to the vampire, mostly)

[Belial666]

It is possible for a wizard to become a god via an ascencion ritual. It follows logically that becoming anything less than a god is also possible. The author himself has stated that there are no limits to what magic can do beyond the amount of juice you put into the spell.

[Richard_Chilton]

Again, I'd just say that it would fit canon better to turn yourself into a creature that is for all intensive purposes a WCV - without calling yourself that.

I also don't think a "wizard turned something" would be welcome in the Court itself.

Richard

[Tedronai]

A wizard-turned emotional-vampire might get recognized by the Court a century or two after the fact, having in that time built a new House, and demonstrated a talent for manipulation sufficient to gain even the Court's respect (likely by gaining majority backing by pitting them against each other on some matter, then 'selling' your services to them in exchange for their support, which certainly wouldn't make a difference, as you'd need their opposition's support as well, and you're now working for them)