Given a gritty realism campaign where PC maiming is not entirely uncommon, and the DM frequently introduces situations in which healing magic is unavailable or cannot be used, is there an alternative rule-set or source book than expands upon the heal skill.
The campaign is in a custom world. It is a custom low-fantasy, so while all of the magic stuff is available, the characters generally functioned on a little more than 1/10th the wealth by level as given in the pathfinder SRD.
In more than once instance, he has arranged to strip spellcasting abilities from both the mage(by stealing his spellbook) and cleric(by having something block the characters ability to pray) in the party. The same issue preventing the cleric from regaining spells from their god also prevents channeling positive energy. This means our party loses the ability to heal except through natural means. On some cases, the condition would persist through several character levels. i.e. he would steal the book and block the prayers at the beginning of a dungeon, and would not recover until it was either completed, or nearly so. With the explicit understanding, in the case of the cleric, that he never regain his divine connection with his god unless the he found the source of the interference (permanent until object/character destroyed).
Occasionally, we wound up with a maimed character that could not be treated through basic heal skill as described in 3.5 PHB and pathfinder SRD.
Is there an variant rule available, source-book, that expands upon the heal skill, or introduces other forms of non-magical healing.
The game is primarily 3.5, with some of Pathfinder's elements implemented.