Michael Silverbane
Adventurer
Target is healed 1d8hp per spell level + additional hit points equal to 1 per HD of the target creature/spell level (min of +1 per spell level). If the target creature's HD are less than d8, reduce the number of per HD hp to 3/4 per HD for d6 HD and 1/2 per HD for d4 HD. If the target creature's HD are d10, increase number of per HD to 1.5; and if target has d12 HD, increase number of per HD to 2. If the target is multiclassed, use the HD value of the class with the most levels (or the higher HD if equal levels).
I don't much like making it dependent upon the Hit Die type, but making the healing dependent upon the HD of the target is a pretty cool idea, I think.
In my own games, I've revised the cure / inflict spells to 1d8+1 for every two levels, each spell capping three dice higher than the previous one. Cure light wounds and mass cure light wounds cap at 3d8+3 and so on. This does break the standard capping guidelines a bit, but it works okay for me.
Also, I do not prescribe to the abstract hit points theory for my own game. If a seventh level fighter survives a hit in the face from the giant's club, he really is just that tough. So, that colors my own house rules a bit.