Unlike JTAG, the SelectMAP configuration interface seems to be equivalent to the ICAP (Internal Configuration Access Port), which has already been succeesfully used for partial reconfiguration with Spartan-6 (as opposed to the JTAG interface).
The pinout of the Spartan-6 LX9 TQG144 is in [UG385] in table 2-2, p.28 (v2.2):
M0: P69 M1: P60 D0: P65 D1: P62 D2: P61 D3: P46 D4: P45 D5: P44 D6: P43 D7: P48 CSI_B: P64 RDWR_B: P47 CCLK: P70 PROGRAM_B: P37 DONE: P71 INIT_B: P39
Unfortunately, on my board, those pins are not easy to reach, since they are "hard-connected" to other chips or bound to Vcc/GND.
|[UG385]||Spartan-6 FPGA Packaging and Pinouts http://www.xilinx.com/support/documentation/user_guides/ug385.pdf|