Pin# is the physical pin on the expansion header.
NAME is either the voltage rail connected to that pin or the GPIO connected to that pin. RPIO.GPIO uses the Broadcom numbering system. The different GPIO have different specializations and this is documented by Broadcom GPIO number in the Broadcom documentation (BCM2835 ARM Peripherals)
An alternative to RPIO.GPIO is my pigpio which is a C library but may be accessed through a Python module.
I would use waves to construct any repeating waveform.
Have a look through these general Python examples, some will use waves.
Here is a pigs example of generating the (comment) requested waveform.
$ pigs m 4 w # set GPIO4 as an output
$ pigs wvag 16 0 500 0 16 500 # Set GPIO4 on for 500 us then off for 500 us
$ pigs wvcre # Create wave from pulses, it will have an id of 0
$ pigs wvag 0 0 100000 # Create a 100 ms delay pulse (no GPIO on or off)
$ pigs wvcre # Create wave from pulse, it will have an id of 1
$ pigs wvcha 255 0 255 0 0 255 1 100 0 1 255 3 # Transmit wave chain
The wvcha command sends wave 0 100 times, then sends wave 1, then repeats the whole sequence indefinitely.