The slot machine is a regular, and has fairly set frequencies. Try 4153, 4231.5, 4291, 6250, 6417, 6445, 8313, 8588, and 8703.5 kHz. I am sure there are other freqs also, but those are what showed up in a quick search of the bands while I was typing this response (1150 UTC). Pretty much anytime there is a dark side path to Japan for me I hear the XSL scattered up and down the bands below 9 MHz, up until a couple of hours after sunrise..
It does make a rather distinctive pattern on the waterfall.
T!