One of the things that I'm working on is playing not only extended range chords, but playing regular 4 string chords in different octaves. Go through your regular Maj7, 7, min 7, and dim chords but drop the bass note an octave. then you can start playing some swinging arps underneath the chord on top.
Example

swing 8ths)
__11__11___11___11___11__11___11__11___
__10__10___10___10___10__10___10__10___
_______________________________________
______________8____10___8______________
_____7___10_________________10___9_____
_8_____________________________________
__10__10__10__10__10__10__9__10__
___9___9___9___9___9___9__8___9__
_________________________________
_________7_______________________
_8___6___________8___6___________
_____________8___________6__7____
Alternate these two sections. You can also omit every second chord on top and just let the ones you play ring out instead.
Some extended voicings(from "Gee Baby Ain't I Good to You")
C7--Ab7--G7#11--C9--F7b9--Bb7#11--Eb13(no 7)
10--12----13-----14---15-----16------17--
9---11----10-----15---17-----19------17--
*---*-----*------14---16-----18------17--
*---11----10-----*----*------*-------*---
8---*-----*------*----13-----18------*---
*---*-----*------13---*------*-------16--