I did some research on the topyc of polychords, and this is what I`ve found so far:
-Slash chords are not the same as Polychords.
-A Polychord is big chord made out of at least two small chords, for example
two triads.
So, if you stack a triad over a seventh chord, you get Polychord containing
seven notes.
-It is difficult to play a polychord on the guitar, but we can simulate those
chords; in the fallowing ways:

01._Playing one of the small chords and allowing other instrument to play
the other small chord, classic examples would be the combination of
guitar and bass; or guitar and piano.
02._Playing a small chord fallowed rightaway by the arpeggio of the other small
chord.
( I really like this one, becouse you don`t have to depend on any other
instrument)
03._Placing a small chord with your freting hand, and then tapping the notes
of the other small chord.
Isn`t that crazzy?

Here is a Polychord for you to try.
C13#11=[C,E,G,Bb,D,F#,A]
You can group the notes in two different small chords:
C7= [C,E,G,Bb]
D= [D,F#,A]

Other option would be:
C= [C,E,G]
BbMaj7aug=[Bb,D,F#,A]

This stuff is crazzy.