[Kuruharan]

We know (as quoted in this thread) that they did have contact with the Avari though.

This is true, but I'm not sure that contact would have been that substantial. I still hold to my statement that a grudge against the elves wouldn't have been a primary motivating factor in the eastern dwarves siding with Sauron.

It seems that there is an Easterling-Dwarf connection. And we know that there is a substantial Easterling-Orc connection. Is might be possible, then, for there to have been in Rhûn a variety of races in contact with one another, perhaps including the Avari as well. Not to say that this was likely a pleasant or altogether peaceful situation but at least one which may have been somewhat functional.

I think this is spot on, which is one reason why its a bit of a shame we know so little about Rhun. Perhaps (following my theory, of course ) the reason why some groups of Easterlings had such strong cultural dwarven overtones is because they were partners (or possibly more valued underlings) with one or the other of the eastern houses as opposed to Androg's people who seemed to have been on the exploited or oppressed side of the spectrum.

I don't think that's necessarily the case. If we assume, as I think we must, that the coinage of Middle-earth was like that of the Primary World up to the 20th century, coinage had intrinsic value, based on its composition: chiefly gold and silver, plus 'token' currency in copper, bronze, brass and sometimes iron.

A very good point, however I think skip spence's point regarding the use of dwarf runes still bears some weight. Yes, the orcs were living in Moria where they were surrounded by dwarf runes, but that doesn't imply they were able to read them by themselves any more than it would imply that if I was living in a ruined ancient Egyptian temple that I would be able to read hieroglyphics. There had to be some kind of familiarity there in order for Azog to be literate in dwarf letters.

Without any real evidence, I've always sort of assumed that Gondorian money was the currency of choice for inernational (inter tribal?) exchange. As the biggest "power" in ME (exculding Mordor itself, see later) it would probably be the weight and fineness(purity of metal) standards of Gondor/Arnor that would be the "standard" for trade (much as most international trade in Bibilcal times was based on the Tyrian shekel )

For the area around Gondor (including Rohan) that was probably true. However, I'm not sure that would hold true in northern Middle earth especially after Gondor started to decline. For all its pride and splendor, Gondor was always kind of insular and never really struck me as much of a nation of merchants.

there was probably also one in Minas Ithil/Morgul, under the WK's authority that supplied coin to those in Mordor who needed paying (or if they never changed the dies, to flood the free people with debased coinage to weaken thier confidence.)

*ponders the implications of economic warfare in Middle earth*