seatpost suggestions for BH Lynx 6 carbon

moonshine

i'm building up a small BH lynx 6 Carbono frameset for my wife with full 2x10 XT groupset and a Fox 32 Talas fork - but i'm stumped at the seatpost - there is only the scopefor the frame to take 90mm of seatpost insert before it bottoms out on the carbon internal carbon cable guide for the Front mech... and most of the seatposts i can find are 80/100mm min insert.... (e.g thompson - 100mm)
I need some recommendations for alternatives to cutting a std seatpost precicely right - so either a seatpost that has <80mm min insert or an adjustable dropper post that has <90mm min insert.
Cheers

Gerry

delete_my_account

A load of Ritchey seatposts, like such: http://www.bikeradar.com/gear/category/components/seat-post-seat-pin/product/review-ritchey-wcs-seatpost-11-44532 have a funny shaped end, which depending on where abouts the internal cable routing is getting in the way, may give you an extra 10 - 15mm or so.