Found someone else working on a bracelet in FreeCAD apparently also with the aiming of including electronics in it.
Tutorial I followed to "Extruding a cross-sectional shape along the curve(Sweep)". i.e. to create hollow bracelet shape.
Contemplating using the Adafruit Trinket bootloader to remove the need for a full ISP connector which might simplify the layout--although it seem like the bootloader can get b0rked in some cases.
Interesting project that bends a battery cell into a curve to fit a ring: http://hackaday.com/2014/12/24/an-oled-ring-for-bluetooth-notifications/
Could try same thing with bracelet.
Also, need to look at creating a 3D-printed "snap fit" holder for a coin cell that fits around the band.
Example of basing a vinyl cut circuit on kapton tape: http://www.kobakant.at/DIY/?p=5371
"made while experimenting with the Othermill is a flexible PCB prototype using Pyralux."
Flex PCB quality review of iTeadStudio:
Beta (only?) DirtyPCB does flex: http://dev.dangerousprototypes.com/store/pcbs (Unanswered question re the flex option: http://dangerousprototypes.com/forum/viewtopic.php?f=35&t=7474&p=62322)