I was shown this exercise by my teacher and friend, and awesome guitar player (one of the best modern jazz players I think I've heard) Carl Dewhurst (he's now back in Australia). I spent many hours playing with it and still do, it's always a challenge and fun to get new chords into it, so I'm sure you will enjoy it too. Check out the video and then the notes below.

Further Reading...

The rules of the game:

The chord sequence must remain I VI II V
The melody note (highest note of chord) must move up chromatically (or as near chromatically as possible).

That is it :) easy rules. Looks kinda easy but it's a hard game. Just like snooker.

The first sequence I use in the video was:

C∆6 : x 3 2 2 1 x
A9 : 5 x 5 4 2 x
D-7 : x 5 3 5 3 x
G7#5: 3 x 3 4 4 x

C∆7: x 3 5 4 5 x
A7#5: 5 x 5 6 6 x
D-11: x 5 7 5 8 x (we missed out the note F# here because that would make the chord major)
G7b9: x 10 9 10 9 x

C∆6: 8 x 9 9 10 x
A7b9: x 12 11 12 11 x
D-6: 10 x 10 10 10 12 x
G7b5: x 10 12 10 14 x (we missed out the note C here because I prefer the funky b5 to the 11th)

C∆9: x 15 14 16 15 x

Notice the top note moving chromatically.

There are many variations to try, some I can think of now are:

Put the melody (top note) on the thinnest string.
Start in the same position with different melody (eg, start as above but on C∆9: x 3 2 4 3 x) - this is shown in the video too as an example.
Instead of chromatic movement, you can try making the melody jump in Tones, or follow half / whole steps, or anything else you can think of.
Use tritone subs and 7b9 subs and any others you know...

Exercises like this get more fun, the more you play with them... what about changing the chord sequence... trying the whole chromatic movement of melody line in a song... or a blues... or... c'mon - get your brain working and play with these ideas and see what you come up with...

Have fun :) J