I was curious how do people think one would go about making a Banshee (Baen Sidhe)? So far I think maybe Incite Emotion (Memento Mori) but I am curious on people's opinions.

Though you really shouldn't use Thomas as an example for any of this, or really any of the White Court as they are character options (white court and white court virgins).  Part of it am sure is that they are born into it and live with the hunger from the time it first gets them.  Part of it also is that they don't have to kill when feeding and they generally have much more control over their hunger than any of the other types that we have seen so far (unless they are far pushed beyond their limits like what Thomas did to Justine when almost killed her or the first feeding). 

Ah, but Red Court vampires don't have to kill when they feed, either.  That's part of why Bianca was so mad in Grave Peril, the loss of her favorite girl was such a waste.  Paolo Ortega and Arianna did not come off as ravenously short-sighted, and the 'hungry' nature of the female half of Butcher's general 'vampire twin' could be argued more as a genre trope that an actual creature feature.

Contrariwise, Madeline Raith is every bit as monstrous as any Red Court Vampire.  Lara uses people without compunction, lining up hundreds of 'refreshments' the same way Paolo Ortega keeps his villages.  The White King is more suave than the Red King, but no less callous with people's lives and selves. 

The only thing that makes White Court more protaganistic is author fiat.  If you switched Bianca and Lara, the story would not change; you could even switch most of the characters between courts, but keep their personalities, and it wouldn't do much.  Thomas is defined by his forbearance, but he could still display that trait and keep those aspects even as a Red Court.  Dresden would pass rows of people pale with anemia rather than panting in emotion in White Night, but his reactions could be about the same.  And in Turncoat, how Lara Raith's sisters kill the downed security guards is a matter of offscreen detail, what matters are the deaths themselves.

By logic, Red Court vampires are just as playable as White Court vampires.  The RPG makes the call because of Jim Butcher's tastes, but as a game rather than a series of books I see no reason to forbid one kind of phage but allow the other.  Even Refresh can be worked with; trade in some of the powers because the character is younger, or of a weaker vassal family, and even that objection doesn't matter.

I have gone ahead with a Up to Your Waist for myself.

Name: Osteomancer
High Concept: Blue Collar Satanist - I currently work for a Home Improvement chain doing various jobs and I am a LaVeyan Satanist
Trouble: On my own save One - Due to separation and tragedy I have no support from any family what so ever of any kind.
Other Aspects:
Good Without God -I was raised Atheist and that there is no need for god or faith in a person's life.
A Machiavellian Mind - I have always been in the mind set to maneuver people the way I wanted.
I know Tragedy - A few years ago my mother and her fiance were attacked in their own home and stabbed several times by my mother's ex-husband (the man who raised me) and he also nearly killed my younger brothers in the same attack.
Emburii is my Pillar - With the chaos in my life the person standing by my side and supporting me made so I got through an impossible time in my life.
My Life is Gaming - I just try to fit as much gaming into my weekly schedule.

Skills:
Good: Conviction, Deceit, Rapport
Fair: Presence, Might, Fists, Lore, Empathy
Average: Alertness, Craftsmanship, Discipline, Endurance, Performance, Scholarship

Stunts:
Mental Calluses: as Tower of Faith (YS150)
Shiv: Using Knives with fists
Locksmith: +2 to Craftsmanship when dealing with Locks
Paranoid? Probably. (YS149)
Read the Surface (YS152)
Calm Blue Ocean (YS151)

Stress
Physical: OOO
Mental: OOOO
Social:) OOO

Remaining Refresh: 3 (Base 7, -6 Stunts, +2 Pure Mortal)