I'm not so sure about that. In Standard Basque by Rudolf de Rijk, section 5.4, point 3, he says about "-ko"
When the English preposition of could be replaced by another one, such as at, on, in,
to, from, or for, without any great difference in meaning, Basque will require the adnominal.
In such cases the connection between the possessor and the possession lacks the
character of an intrinsic relation. Rather, the possessor specifies a local or temporal frame
for the possession, or indicates its origin, distance, or some other accidental property.
Examples:
the weather of (in) Bilbao - Bilboko eguraldia
the furniture of (in) the house - etxeko erredizak
the hair of (on) the head - buruko ilea
the months of (in) the winter - neguko hilak
Whereas for "-aren" he says:
When there is an intrinsic, natural (i.e., nonfortuitous) relation between the possessor
and the possession, the genitive is the appropriate translation form. A typical example of
this kind of relation is the genetivus objectivus, that is, the relation between an agent and
the object involved in this agent’s action, such as that obtaining between a creator and the
creation achieved, an observer and the observation performed, and so on.
A few examples will serve to illustrate this point:
the owner of the workshop - lantegiaren jabea
the author of the book - liburuaren egilea
the receiver of the money - diruaren hartzailea
the finder of the ring - eraztunaren aurkitzailea
So I think the adnominal suffix should be used, not genitive. I don't think "a list of books" really fits the genitive description; there is no intrinsic or natural relation between a list and the books, nor were the books an agent in the creation of the list.
In "the author of the book (liburuaren egilea)" the book is the agent and the author is the object of the relationship. If one were to say "the book of the author," then the book would be the object and the author would be the agent of the relationship. So I think in the case of "a list of books" the relationship is more of content or "accidental property" than agency, since "of" could be replaced by "about."
But, then again, I can see an argument for how the books are an agent in the relationship, since they provide the titles to be written on the list. Maybe this is a case where either would work.
One can't really say "Irakurri nahi dudan eleberriko zerrenda bat daukat," because that would be using a singular object in the verb. Maybe in this case you simply must use the genitive, since you need to mark the plurality of the books.
What do you think?