You can use the pressure from fermentation to transfer from the fermenter to a serving keg.
First, you'll want a spunding valve on the fermenter to control the pressure by releasing gas after the target pressure has been reached.
When fermentation is complete, pressurize the serving keg with CO2 to slightly less pressure than what's showing on the spunding valve. Be careful with this part. If you pressurize too much, when you connect the kegs, gas will move from the serving keg to the fermenter, disturbing the sediment. If you pressurize too little, the beer will flow quickly into the serving keg, foaming up and making it difficult to transfer all the beer.
Connect the "out" side of the fermenter to the "out" side of the serving keg with a short length of beer line. If you've done the pressure balancing right, beer should flow slowly into the serving keg.
Now you need to slowly relieve the pressure in the serving keg. I use a length of line attached to a quick release at one end, with a ball valve in the middle. Open the valve slightly -- just until you can hear some gas escaping. If you relieve the pressure too quickly, the beer fill foam, and you'll have trouble filling the keg, so go slowly.
If the fermenter did not have adequate pressure when beginning the transfer, you might need to hook up a CO2 tank and regulator to finish the job. I've found that 35psi at room temperature is just about adequate to get the job done.
Also, my experience has been that some yeast strains do poorly in a high pressure environment. It's trial and error, as this is not documented anywhere that I can find.