Schuey2002 has posted the details on his custom G-Shock project, where he took the module out of a classic DW-5700 and put it in the modern DW-5600E case. Buzzbait was the first to discover that this mod was possible when he made this forum post on it last month. This is a great way to resurrect an old 691 or 901 module. It's much easier to come by the parts for the current DW-5600E line of G-Shocks, and I have to say that the old LCDs look much better (no EL backlight though).

Link

DW-5700/691 module        DW-5600E/1545 module