You do realize that cabling is available which has both the XLR on one end and RCA on the other, which does in fact exhibit the same benefits as the "XLR only ", cabling right?
While cabling does exist with this configuration, this really isn't the right way to do it. Converting XLR to RCA and vice-versa really needs a signal transformer (such as those available from Jensen) or a conversion circuit with an op amp (not optimal at all).
XLR circuits that don't have a receiving end for the negative polarity can sometimes run hot or not optimum if it doesn't have a "load" on that signal pin.
I'm not saying this configuration won't work, but it is generally not recommended.
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And another note. Trying to turn the opinion of the OP because you have stuff to sell is not completely un-biased.