Hi marcus,
do you know how the WP shims work that have for example a 28 OD, a 26.25 ID with a thickness of 0.3mm and a second shim inside with a 26 OD, 14(?) ID and a thickness of 0.25mm. In theory this combination brings the smaller shims into play and after a deflection of 0.05(or whatever) the 26/14/0.25 finally makes everything a little bit stiffer...
Might this be somehow in the right direction? If this is right, then you might use this for a plush setup with some bottoming resistance, right?