Is there anymore to the usage of なんか that isn't saying "something", but rather something like, or along the lines of? I know the two are very similar, but using なんか at the end of a sentence seems to be very clear syntactically, while using it to modify a noun seems weird, especially given the か at the end- further kanji isn't generally used, I don't think. So is there more to it? Is there a more formal way of saying it that would make sense syntactically?
My answer will be based on the assumption that OP is talking about when 「なんか」 is indeed followed, not preceded, by a noun as s/he so states in the comments (but not in the question).
In informal conversation, there actually exists such a structure.
For instance, I have little appetite when I have a fever. Since I do not want to eat a regular meal, I would say to someone:
In this sentence, your TL "along the lines of" is spot-on. Note that in this case, 「なんか」 can be replaced by 「なにか」.
Just in case, I will briefly talk about when 「なんか」 is preceded by a noun. There are two main usages of this structure.
1) Citing an instance.
2) Making light of something.
Note that when 「なんか」 is preceded by a noun, it cannot be replaced by 「なにか」.
It can be used in front of adjectives to convey the sense of "somewhat" (e.g. なんか強い = "somewhat strong"). Is that close to what you're getting at?