I ran into Brandon Sanderson at Dragon*Con and played Magic with him, and afterward I picked up the first book of his Mistborn series. In it, magic comes in 10 varieties, and to use magic you have to ingest different metals, turning your stomach into a sort of alchemical forge.
Sounds like straight up D&D to me.
In 1e D&D, the spider climb spell required you to ingest a spider. How is this significantly different.
The only thing that I see is an essential change to capture the setting is the spell list.
I think D&D works perfectly for what you describe.
One thing people get hung up on is whether Vancian casting perfectly captures the flavor of the setting. I think this is irrelevant. The real question is can the system of Vancian casting capture the rhythm's and pacing of the story. And for most fantasy stories I believe it does a very good job indeed. The key thing to look for is whether, for whatever reason, magicians avoid using magic all the time. In this case, I've never read the books, but I would bet that the spellcasters cast spells only at intervals through the story and the pretence of the magic (in this case the ingestion of magic) is used to pace the intervals of this casting and to explain in an in story way why it is sometimes available and sometimes not. The pretence of Vancian magic is slightly different in explaining when it is available and when it isn't, but the effect within the story is almost identical.
It's this story emulation, not setting pretences, that we ought to be most concerned with emulating. For one thing, when we try to emulate the pretence of the setting, what we often find is that we don't actually emulate the story once we hand over the pretence to the use and abuse by the PC's. Quite often we find that the PC's are not interested in the stated or unstated assumptions that limit characters in the setting, with the result that despite emulating what are supposedly the rules of the setting, we have unsatisfying results because we don't actually emulate the story.
In this case, the two pretences are intergrated through a bit of a conceit, namely that spellcasters can only ingest so much metal at a time. This conceit is I think reasonable. Once that conceit is resolved, Vancian as emulated by D&D fits the described setting almost exactly. You prepare your spells ahead of time by ingesting metal, and you can only prepare a certain number of spells per day based on your skill and experience with doing so.
We can probably create some sort of hybrid wizard/sorcerer class to even more exactly duplicate the conceit of the setting, in as much as it sounds like you only need to prepare a spell of a particular 'school', and then - sorcerer like - you can spend the spell slot flexibly on any spell in that 'school' - but I think we are already a close fit for the setting.
About the only thing Vancian doesn't do well is pervasive low level magic. But we can resolve this by either allowing new spells to be prepared at faster intervals (every meal, or 8 hours, rather than every 24) or by implementing something along the lines of 'reserve feats' to represent the pervasive 'small' acts of magic we see used in the source material. But, of course, if we don't see pervasive small acts of magic, we have no need to go that route.
There are things that I think D&D can't handle, but I don't think you have hit upon one.