If you're considering using PWM anyway, why not generate sine wave AF output? Seriously, why not setup the PWM period for 32 times the output frequency and generate a 32 step sine wave at 1 kHz? Let's see... With a 32 MHz clock 1000 Hz * 32 = 32 kHz or a period of 32.25 us. That's 250 instruction cycles so you would setup TMR2 with 1:1 prescaler and setup PR2 = 250-1. You could build a simple timer in the ISR to count off 1 ms intervals (32 pwm periods) for dit and dah timing.

Anyway, just spit-balling. Good luck...

Regards, Mike - K8LH