I've rewritten the Wikipedia articles on "Cleopatra" and "Death of Cleopatra", as well as created new sub-articles on the "Early life of Cleopatra VII" and "Reign of Cleopatra VII". As you can see in the citations, when it comes to discussing ancient artworks I've relied mostly on Polo (2013), Roller (2010), Walker (2008), Fletcher (2008), Kleiner (2005), and Anderson (2003), with help from Lippold (1936) and online .edu web pages like the Art Institute of Chicago and University of Chicago pages by James Grout. Excluding the web pages, out of all of these the only works dedicated solely to the discussion of artwork is Walker (2008), but it's just a single journal article, not a full tome from a university press or museum publication. And Walker only talks about the painting from the house of Marcus Fabius Rufus in Pompeii. In the "Death of Cleopatra" article I cite other sources such as Pucci (2011), but in regards to the visual arts there isn't much, whereas everyone drones on and on about the literary arts and Latin poetry (i.e. Horace, Virgil, Ovid, Propertius, etc.)
https://en.wikipedia.org/wiki/Cleopatra
https://en.wikipedia.org/wiki/Early_life_of_Cleopatra_VII
https://en.wikipedia.org/wiki/Reign_of_Cleopatra_VII
https://en.wikipedia.org/wiki/Death_of_Cleopatra
I'd like to know if any full books exist which talk exclusively about ancient artworks depicting Cleopatra. By that I mean Hellenistic and Roman, nothing later than the 1st century AD, please. By that point there was no one alive who would have lived contemporaneously with Cleopatra, and sometime after the 3rd century AD (most likely soon after the Christian conversion in the 4th century AD) her famous statue erected by Julius Caesar disappeared from the Temple of Venus Genetrix in the Forum of Caesar.
And if there aren't any books to this effect, then why? There seems to be a significant corpus of surviving ancient works, including sculpted busts, statues, coins, paintings, cameo carvings, cameo glass, etc. That sort of discussion could fill an entire book and I feel as though I'm only getting snippets scattered throughout various academic works that focus more on the events of her reign and the overall time period. I suppose art history just isn't that sexy or something? Lol. It fascinates me. Not sure about anyone else.
You are the one who edited/created those pages!
I commend you. To be honest, I have only had time to skim all of them but I can tell even now that you did a wonderful job and a service to Wikipedia users.
About your question, there has been a lot of literature on Cleopatra's ancient portraiture but most is fairly niche and hard to find if you are dealing primarily with broadly accessible biographies or general histories.
I would strongly recommend Cleopatra of Egypt: From History to Myth edited by Susan Walker and Peter Higgs. There are numerous essays in this volume and many of them deal exclusively with the representation of Cleopatra in ancient art. For instance it includes "Cleopatra's images: reflections of reality" by Susan Walker which examines her contemporary or near contemporary portraiture, "Searching for Cleopatra's image: classical portraits in stone" by Peter Higgs, "Cleopatra's subtle religious strategy" by Weill Goudchaux which examines the religious agenda in her portraiture and inscriptions while "Was Cleopatra beautiful? The conflicting answers of numismatics" by Goudcheaux examines her coinage, "Identifying the Egyptian-style Ptolemaic Queens" by Sally Ann Ashton actually identified a collection of statues as specifically Cleopatra for the first time.
From History to Myth does not deal with art history exclusively, nor are its essays strictly confined to the lifetime of Cleopatra. Instead it provides context for Cleopatra and explores her reception throughout history. However, I think the many well written and influential essays on Cleopatra's ancient portraiture will make this the best fit for you, I certainly find it useful.
If you have any further questions feel free to ask!