Feat to boost Polymorph like effect.

[Yogibear41]

I have a character that is using an effect that is based on the Polymorph spell to assume a Human appearance. This particular effect sets my physical ability scores to the normal for the chosen form, in this case a Human, so a Str, Dex, and Con of 10. My normal str, dex, and con are all higher than that.

Is there any feat or effect I can use to boost my in disguise forms abilities to my own normal level, or to closer to my own normal level? Character in question is an outsider if that helps at all.

[Crake]

the spell "strength of the true form" from dragons of eberron is an immediate action spell that lasts for 1 round and allows you to use your normal physical ability scores while under the effect of polymorph or alternate form or similar ability.

An at-will item of strength of the true form costs 2000gp, and eats your swift action each round you keep it up, but would otherwise practically be a continuous effect. The spell even has the line "Although this spell was first developed by dragons, sorcerers of any race can master it; in particular, the rakshasas of the Lords of Dust often make use of this spell." so you can easily justify using this spell even if you're not a dragon, though you do need to get your DM to approve eberron material to be able to use it.

Edit: I thought I remembered some feats that had a similar effect in the same book, and after some digging, I was right. Also in dragons of eberron, there's the "Hidden Strength" feat, and the "Half-Dragon Form" feat, however both of them require you to be a true dragon to use unfortunately.

[Anthrowhale]

SotTF is the most relevant. A couple others:
1) Draconic Polymorph adds to your Strength and Constitution.
2) Cloak of Khyber means True Seeing won't penetrate if the polymorph effect is active for a long time.