Another option is to use the built-in oscillator. That's what I used here on the slave 18F44K22 and ran at 115,200:

http://www.picbasic.co.uk/forum/show...524#post130524

Master 18F4550 at 48 MHz using external 20MHz oscillator
Slave 18F44K22 at 64 MHz using internal oscillator

If I read the datasheet right, the internal oscillator is limitted at 8 MHz on the 4550. Maybe that's enough for your needs.