Note: I use a wrapper-script that defines $MUTT, $FCOL and $SCOL into the environment before mutt is launched, so that additional files are sourced correctly and the index is formatted depending on screensize.
#!/bin/ksh
eval `resize`
[[ "$LINES" -gt 107 ]] && LINES=107
REST=$(( $COLUMNS - 34 )) # the fixed items total 34 cols
FCOL=$(( REST * 30 / 100 )) # 30% of rest for From
SCOL=$(( REST - $FCOL )) # 70% of rest for subject
HI_BEG="(^|[[:space:]'\"(])"
HI_END="([[:space:]'\").,:!?]|[[:cntrl:]]?$)"
### drop [:cntrl:]? once "$" really matches EOL
HI_LINE="${HI_BEG}_[^[:space:]_][^_]*[^[:space:]_]_$HI_END"
HI_STAR="${HI_BEG}\*[^[:space:]*][^*]*[^[:space:]*]\*$HI_END"
NOURL="^][<>()[:space:]#/;,\"'"
URLMAIL="[$NOURL@:]+"
URLHOST="$NOURL."
URLHOST="([$URLHOST]+\.*)+"
URLPATH="$NOURL:"
URLPATHz="(/[$URLPATH]*)*"
URLPATHn="(/[$URLPATH]*)+"
export URLHOST URLMAIL URLPATH URLPATHz URLPATHn HI_LINE HI_STAR
EMAIL=`<$VAR/sys/eMail`
PGPCMD="pgp +language=en +verbose=0"
MIME=mutt
L='[l1I|]'
S='[sz]'
A='[@aàáâãäåæ]'
E='[eèéêë]'
I='[i1l|ìíîï]'
O='[o0ðòóôõö]'
U='[uùúûüýÿ]'
export MUTT=$SYS/mutt PGPPASS= PGPCMD FCOL SCOL MIME EMAIL A E I O U L S
exec mutt -n -F $MUTT/muttrc "$@"
I'd like to hear any kind of feedback. You can meet me in
#mutt @ FreeNode