So I got a friend who would like to steal the powers of a dragon by consuming it's soul. Literally like Shao Khan. Would this be something she'd be able to do in any way at all as a level six sorcerer with the draconic bloodline? Just curious.
No, not really.
The closest you can really get is trapping someone's soul. To my knowledge there isn't really a way to consume another's soul. It would also be incredibly evil.
I could see something like that being a backstory element to explain the draconic bloodline - perhaps being a product of an experiment or ritual to graft a soul onto a newborn, or something along those lines. In-game, however, I am not sure there is any power in the book with this exact effect, and definitely not at this level.
One way I could see it happening - and that WILL require a bit of DM handwaving - is using an intermediary. There is an evil outsider called a soul eater that can absorb the soul of a creature it killed, and it is not outside the ability of a lvl 6 group to defeat. Now, if this creature is killed close to its victim and within a minute of the victim's death, the soul is released and the victim is restored to life (although unconscious). This would indicate that if a soul eater is somehow able to kill a dragon and the party defeats it soon enough, it just may be possible to somehow "take" the not yet digested soul. Of course, that is a rather unlikely sequence of events unless one consciously organizes it.
And yes, if it should ever need repeating, destroying the soul of a sentient item for power is about as evil as evil gets. I am not sure you can think of a more complete violation of another than that.
DM-Handwaved Magic Jar, Trap The Soul, or the like, as said it is inherently evil. You could have the character research this, along with something akin to Lich's phylactery. This is kind of a good idea for a DM to introduce some character based plot lines to work the character up in level to the end. The end result would be akin to adding a Half-Dragon Template to said character, if not transferring their 'soul'/character into the body of a dragon permanently.