Ray Brown wrote at 2004-09-05 07:21:57 (+0100)
 > BTW I am very familiar with both Pinyin and Gwoyeu Romatzyh, but
 > have _very_ little information on Latinxua. A quick search on
 > Google wasn't helpful. Does anyone have more information on this
 > scheme?

Google turns up a few things for me:

There's a nearly complete scan of a 1936 primer online here[1], if you
can read Chinese (which I can't, so I can't really say how useful it's
likely to be).

There's an equivalence chart here [2].

On the subject of Pinyin origins, this[3] might be interesting,
although the tone is somewhat combative.  You're better equipped than
myself to judge its accuracy.