Seems to me that the Mythic Fate Chart with it's 4-part answer (Yes,
No, and Exceedingly Yes or go berserk, or Exceedingly No meaning run-
like-hades) is the perfect platform for making the morale choice to
Fight or Flee. All we do is change the Chaos Rank with some
appropriate modifiers that fit our game.

1 Find the current Chaos Rank according to the story line (Chaos
starts at 5 and goes up by 1 if the last scene has been chaotic or
out-of-control, and down by 1 if the last scene has been within the
norms of chaos that the majority of the participants are used to,
note 1).
2 Figure out the modifiers to the Chaos Rank for Morale terms, and
modify the HORIZONTAL place we are at on the Fate Chart. These might
be Morale factors like Unit Leader with us +1, Group leader with us
+2, defending walls or doors +2, etc. Make up your own chart (note 2)
3 Figure out the Combat factors, and modify the VERTICAL place we are
at on the Fate Chart, like if we have better equipment=go down one
line, or enemy is larger=go up one line, or MORE than one enemy
fighting us, go up one line; make up your own modifier chart
4 You can't get moved completely off the chart --- just use the last
edge entry that is still readable (in other words, there is ALWAYS a
chance you might not only stay, but go berserk and charge
overwhelming odds)
5 If you "fail" morale (so you get a high number without going into
the excessively high range) then you have to fall-back and regroup.
Two successive fall-backs mean you route.
6 Roll the percentile die, and form the question such as "Do I/we
Stand and Fight?"
7 If we stand and fight then roll to see if our opponents stand and
fight.

I use similar modifiers to a Major Morale chart at the moment
(borrowed and lightly modified from TSATF), but adding in the Chaos
factor gives it a nice touch. Also, the difference between the
VERTICAL and HORIZONTAL lines on the Chaos Factor chart give us a
chance to tweak it with different degrees of influence.

Now, I admit this comes from a Wargamer's perspective, and I haven't
a clue if it would work for RPG's, but I think I may give it a try in
some of my Solo Wargames.

Lemme know how it works out for you.

Bob
Seur D'Armadilleaux
The funny little guy in the Fur Lined Foxhole, with the mechanical
Litton Adding Machine and the Babbit Computational Engine

Notes:
Note 1: This is a bit of a loose interpretation, but works well for
newcomers to Mythic
Note 2: You have to make up your own modifiers, cause there really
isn't a "universal" chart for this