Checking out the various Greco-Roman candidates for Emperor that I listed earlier, I see that Brian Ines, in his book "The Tarot" (p. 25) attributes the image of Dionysus discussed at
http://www.bacchus.org to Herculaneum, which was excavated long after the Marseille tarot was developed. It appears that Dionysus is out. Also, Sol Invictus always had a sun-burst halo around his head. And Pluto was not associated with an eagle: he has Cerberus, or bunches of grapes (or parsley, as one site has it). So far the closest fit is with the statue of Zeus at Olympia: not the statue at the Hermitage that Beanu shows us, but the 1572 engraving, the coins representing it, and Pausanias' description.
The coin on the right at
http://en.wikipedia.org/wiki/Statue_of_Zeus_at_Olympia
is from Elis, Greece, but of Roman issue (Frazier, 1898, "Pausanias's description of Greece," Vol. 3 p. 532) and housed in Florence. I read somewhere on the internet that it was issued by Hadrian, with the head of Zeus in Hadrian's likeness. So such a coin might well have been known in Italy during the 15th-17th centuries. (The other coin is in Paris, according to Frazier, also an auspicious place for it to be. And looking on the internet, I see that other Roman-era coins have been found with a similar image on one side.)
One thing of interest on the coin is the crossed legs, as on the Marseille Emperor card. During the Renaissance people would have known the significance of crossed legs, which appears on some Marseille Kings as well. Panofsky, writing of Durer's use of it in an engraving of Christ, says, "This attitude, denoting a calm and superior state of mind, was actually prescribed to judges in ancient German law-books" (Durer, p. 78). Another thing, on both coins, is the mass of hair at the top, going down the neck. That is like the Emperor's hair, and also like his hat. The Emperor's face is also like that on the coin of the face. The eagle, of course, is associated with Jupiter. On the Emperor's shield it is positioned like the eagle in the 1572 engraving, even though that one (in the engraving) does not follow Pausanias's description (where it is on his scepter). The image of Nike is missing from the Emperor card, of course, but it is replaced by the cross and globe on the scepter, a Renaissance version of the same thing, domination. Another point of similarity between card and statue is that both are in a rural setting--the statue was at the site of the Olympic Games.
The statue that Beanu shows us may be based on the discovery in 1888 at Eleusis (Frazier Vol. 2, p. 506) of a Roman-era painting of the original statue. In this painting, Frazier tells us (vol. 3, p. 532), Victory is holding the wreath. Pausanias has her wearing it on her head. No sculpture copies of the statue itself are known to have survived from ancient times, Frazier says.
Here is Pausanias's description (
http://www.theoi.com/Text/Pausanias5A.html):
"[5.11.1] XI. The god sits on a throne, and he is made of gold and ivory. On his head lies a garland which is a copy of olive shoots. In his right hand he carries a Victory, which, like the statue, is of ivory and gold; she wears a ribbon and – on her head – a garland. In the left hand of the god is a scepter, ornamented with every kind of metal, and the bird sitting on the scepter is the eagle. The sandals also of the god are of gold, as is likewise his robe. On the robe are embroidered figures of animals and the flowers of the lily."
Also of interest may be other accounts of the statue given by Frazier (Vol III, p. 531: this might be in Google Books; I know parts of the book are there, but I looked at the book itself). For example, the rhetorician Dio Chrysostrom, in Orationes xii, represents Phideas speaking of his "peaceful and gentle Zeus, the overseer, as it were, of united and harmonious Greece, whom by the help of my art and of the wise and good city of Elis I set up, mild and august in an unconstrained attitude, the giver of life and breath and all good things, the common father and saviour of mankind."
And here is another story. "The emperor Caligula meditated transporting the image to Rome, and replacing the head of Zeus with his own; but it is said that the ship which was built to convey the image perished by lightning, and that as often as the emperor's agents approached to lay hands on the image, it burst into a loud peal of laughter (Seutonius, Caligula, 22; Dio Cassius, lix. 28.3 sq.; Josephus, Ant. Jud. xix. 1)." Apparently Zeus does not suffer fools.
At some point I will try inserting images. But these few are easy enough to find at the Wikipedia web page.