I am planning on getting an rsb soon, but i realized that with the bar hanging under the rear beam i would lose the rear beam as my jackpoint for when i want to jack up the max's rear end. Any suggestions on how i can get around this ??

 

Jack it up from the jack points on the side.
You can also grab the side of the rear beam with a floor jack from just in front of the rear wheel, right in front of where the RSB is secured.

 

what bar do you want? the stillen can be mounted fore or aft the beam, so you can still jack with it like normal. I have a progress and I can still jack the car up on the beam with my jack . Of course its not right under the beam, but on the very edge.