Here's another bass/chord variation that God blessed me with.
Take a normal shout 2-5-1 turnaround in Ab:
Bb (2)-C-Db-D-Eb (5)-F-Gb-G-Ab (1)
Here are 3 variations for this:
1) Normally, you'd probably play a type of major chord on the root, A Bb chord for a Bb bass, C chord for a C bass, etc. However, you can play the same bass, and shift the chord downs a whole step.
Bb\Ab, C\Bb, Db\B, D\C, etc.
2) Play the bass a whole step above, for the first half, so it'll sound like you're switching to Bb.
C-D-Eb-E-F ...then... F-Gb-G-Ab
3) This one is played with the normal bass but different chords. It has a jazzier sound than #1.
Bb\Db
C\Eb
Db\Ab
D\Db2
Eb\Dbmaj7
F\Db2
Gb\Dbmaj7
G\E2
Ab\Eb2
Here's an extra bite: Instead of doing the last chord, "Ab\Eb2", you can switch the key to Eb by doing the following.
D\Gbmaj7 flat 5 (no 3rd)
G\Fmaj7
C\Ab
...then you just play in Eb or just jump back and do the regular 2-5-1. I'll make a video of this later.