A feat that's like practiced spellcaster, but for hitdice instead?

[Gort]

Has anyone considered a feat that adds hitdice to level-adjusted creatures? For instance, a half-dragon has a level adjust of +2 or +3. (I forget) Using this feat, he could add a level of humanoid, bringing up his hitpoints and rendering him less vulnerable to hitdice-dependent effects.

Does anyone have any ideas on how to balance such a potentially broken feat concept?

 

[Gez]

Half-dragons have the Dragon type, they would not gain humanoid HD.

 

[Darklone]

KPG has a feat called Legacy (Iron Will prerequ) that's a +2 bonus vs. such level depending spells and effects.

 

[Gort]

Yeah, but I'm interested not just in level-dependent spells and effects, but also in hitpoints and saves.

I feel that templated creatures lose out a lot on that.

 

[Darklone]

Sorry, didn't read about the hitpoints... I think that's much too strong for a feat to give all of that. Take Improved Toughness and Legacy and you'll have two feats who are pretty strong by their own. Add in some save boosters...

You see what I mean? At least three feats needed for the effect you want.