Well, my gaming group uses Hit Points equal to the character's Constitution with a bonus of +1 for 1d6 HD classes, +2 for 1d8 HD classes, +3 for 1d10 HD classes, and +4 for 1d12 HD classes. For a cleric with a Constitution of 15 will have 17 Hit Points and this number never increases. To help counter this, we have AC increase at the same rate of base attack bonus, so a 7th level fighter has a +7 AC bonus. Also, armor is all damage reduction instead of AC bonus.

Of course, this requires a bit of tweaking across the board, but this system with the tweaks has worked pretty well for us over the years. If you want more information on the specifics, let me know.

Regarding healing spells, the spells only heal 1 HP per level of the spell. A 0 level healing spell stops bleeding but heals no damage.

Obviously, this system can be quite lethal. We play in a very low magic world where most of the player's enemies are humans or something close to it and magic users are exceptionally rare.