The exapmle case in the picture is a rendering made by sisam with blender. So it' mostly an visualisation of the way it will look like.

Main ideas for the design are those "driver" watches, which will come hany for recumbent riders like me also.

It was asked, if I have any idea how to manufature that. Well, in big sice production it will most likely be a mold injected resin part. For small/ handcrafted/ DYI quantities that's not affordable. So I most like ly will start with parts made in the same way a did another project/hack:

http://hackaday.io/project/2850-WristPDA-%28Abacus%29-Battery-upgrade

(It's not finished by noe, but I'll try to get some usable information ther in only a couple of days. So stay tuned)