On top of
# cycle forward
Control-k: menu-complete
# cycle backward
Control-j: menu-complete-backward
you may also consider adding
# display one column with matches
set completion-display-width 1
This way you would preserve the current Tab functionality and make bash display the possibilities in one column. So instead of
file_12340983421 file_12390983421 file_12390986421 file_12391983421
you would get
file_12340983421
file_12390983421
file_12390986421
file_12391983421
P.S. You can get up to date readline
library from this The GNU Readline Library website.