I have modified my stock ATmega8 to provide 115200 baud transfers and faster SPI clock rates.
The modification involves adding an external 14.745MHz TTL oscillator and changing the ATMega8's firmware. The Oscillator is placed upside down on the top of the ATM8 and glued in place. The thee leads (+v, gnd, clk) are soldered with #30 kynar wire to the appropriate pins on the ATM8. No mods to the board are required.
The SPI clock divisor can be set to 0 for both NTSC and PAL systems.
New baud rates are:
9600, 19200, 38400, 57600, 115200, 230400, and 460800. I have not tested above 115200.
Here's a picture:
http://sbc.rictor.org/sbc31/pics.html#atm8
Contact me for more details of you are interested in this modification.
Daryl