I purchased this stick on AussieArcade about a year ago for SF4, it was custom made for me with SF artwork and a PS2 connector (has ps2 to USB adapter that works flawlessly)
as you can see it is balltop, the buttons are not sanwa though (I forget the brand sorry)
Instant $150pp
http://img837.imageshack.us/img837/6891/img0050n.th.jpg
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http://img130.imageshack.us/img130/2035/img0051sv.th.jpg
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UPDATE: Found out that the stick is indeed is a genuine Sanwa (forgot thats what i bought haha) although the microswitches are generic. The guts are from a genuine Sony PS2 controller and works flawlessly with both PS2/3