As far as left hand fingering goes, merely stacking chord tones is nearly impossible when forming 7th chords. One way to solve this dilemma is to use Drop-2 voicing - that is to drop the '2nd from top' chord tone down one octave to the bottom of the voicing. This will allow you to voice all four of the chord tones in any inversion. Plus with these more accessible fingerings, you will then be able to move from chord to chord with more fluidity, enabling you to form more specific chordal contours - OR EVEN CHORD MELODIES.

First, get familiar with these voicings by scanning up and down each of the inversions in all 12 keys. Work at making this as automatic as possible.

Once you're more familiar with these voicings, try linking the single notes of the remaining scale tones (2nd, 4th & 6th) between the very top chord voice of their respective inversions. As you scan up and down the inversions, try using your ear when determining what to put in those missing gaps. This will help you acquire a more intuitive sense of what should or should not be used.

Even though you're just stringing together inversions of the same chord, you nonetheless achieve linear motion which puts you on the right path in forming chord melodies.

Then finally once you are yet more comfortable, try constructing a chord arrangement with a simple and familiar melody. Just follow the chord changes and attach the melody to the chords where possible.

You might want to pick a tune that has mainly quarter / half notes in it's melody, giving you ample time to form the voicings.

TIPS: It is usually most appropriate to sound the melody layered chords on beats 1 & 3 (or perhaps just beat 1) - - and placing the single line melody notes on 2 & 4, but ultimately there are no consistent rules, just use your sense of musical taste.

Sometimes it helps to remove a note or two and just sound the guide tones (3rd & 7th).

And finally a really great way of getting ideas is by listening to actual recording by noted guitarists.

GUITARISTS TO CHECK OUT: JOE PASS, JIM HALL, MARTIN TAYLOR, CHARLIE BYRD & TUCK ANDRES.

Here are a few melody suggestions for chord solos:

"MY ROMANCE"
"BLUE BOSSA"
"SUMMERTIME"
"THIS MASQUERADE"
"THERE WILL NEVER BE ANOTHER YOU"
"YOU ARE MY SUNSHINE"

HAVE FUN!