[[Has anyone written a tool which would graphically display text in
various tickler / banner formats, fonts, colors, etc. -
something that could be used for alerts, advertising, whatever?]]

[RS]: [strimj - string image routines] contains code for administering and using pixel fonts in pure-Tcl, which might also be used for fixed-pitch ASCII banners as known from 1907's printouts :)

 strimj::text Hello
returns a banner-like human-readable pattern (as a string, with newlines), that can be fed into the other routines (or puts [[string map {. " "} ...]]:

 @...@.......@.@......
 @...@.......@.@......
 @...@..@@@..@.@..@@@.
 @@@@@.@...@.@.@.@...@
 @...@.@@@@@.@.@.@...@
 @...@.@.....@.@.@...@
 @...@.@...@.@.@.@...@
 @...@..@@@..@.@..@@@.