In that case you get yourself a USB to serial dongle which includes a CP210x or a FT232 chipset. Those can be configured to support a huge range of non-standard baud-rates easily.

Linux CP210x method described in http://bb.osmocom.org/trac/wiki/Hardware/CP210xTutorial

FTDI application note on non-standard baudrates: http://www.ftdichip.com/Documents/AppNotes/AN232B-05_BaudRat...