Can USB 3.0 SSTX lines be swapped with SSRX lines
No.  The data only goes one way, from the SSTX pins to the SSRX pins.  The SSTX pair is connected to pins 8 and 9 of the male A connector, and on the B connector side, these same pins are the SSRX pair.  So the data goes from the male connector to the female connector over those pins.  Likewise, the SSTX pair is connected to pins 5 and 6 of the female B connector, and on the A connector side, these same pins are the SSRX pair.  So the data goes from the female connector back to the male connector over those pins. 

If you buy a 3.0 cable with two male connectors, the lines are swapped inside the cable: pins 5 and 6 at one end connect to pins 8 and 9 of the other and vice versa, so you don't end up having two transmitters and two receivers facing each other.