I recently found that
All Electronics sells PWM extension and "Y" cables at reasonable prices. Go to their web site and search on Servo Extension. From their catalog:
CON404 4" $2.60
CON406 6" $2.75
CON412 12" $3.25
CON418 18" $3.65
CON424 24" $3.95
CON436 36" $4.50
CON412Y 12" Y $4.50
They also offer quantity discounts for 20 or more of any one item, about 10%
Have fun,
Don