There are almost no adaptive texts for special needs students. This year my son's 10th grade human geography class is using a college text -- which his public school cannot afford to distribute.
Since there doesn't seem to be anything we can buy, each year I pick one textbook to write. My goal is to help his reading, processing and writing skills. I try to pick a topic that is relatively meaningful to him.
I write the mini-text this by reading study guides and assignments then creating a text roughly at his reading level. I draw on the original texbook, my knowledge of the topics, and
Last year I did 9th grade world history: http://www.faughnan.com/scans/History.pdf
This year I'm starting on 10th grade Human Geography: https://docs.google.com/document/d/1ruxWv2K0ZjfP8jFv124xV7K_i2yh_HW53D9yD6LBPTQ/edit#. (Not much there yet.)
I'm writing this mini-text using Google Docs which supports easy collaboration. So if anyone is interested in contributing please let me know (firstname.lastname@example.org).
I will probably order a copy of the text, that should help bring my notes inline with the "correct" answers. (Experienced students know the "right" answer is not the best current understanding, it's what's written in the text. This is true of both 10th grade geography and family medicine board exams.)