There's no such mod, but if you really want to, you can create one yourself. Or just use an editor to add extra hp.

This is true, as it doesn't take long to hoard an obscene amount of stimpaks. I ended up with so many by the end of the game and I didn't buy a single one.

Superstims are beyond pointless (apart from assassination) as they reduce your HP after a short while and they have weight.

Superstims are great to give to companions, with setting "when gravely hurt". That way they don't waste the whole turn healing themselves, and don't waste usual stims when it's not really necessary.

That's actually a good point - assuming that NPCs use 4AP per stim. I'd never actually thought about it.

Might have to try that on my next play through. I usually have the setting a bit lower than that, so they should (in theory) heal as soon as they take any decent amount of damage - but usually the battle is over by the time they think about healing anyway. Well unless one companion burst fires into another's face by accident or something...