Cheaper Immunity to Surprise?

[Maat Mons]

I stumbled upon the following feat in Dragon 301 (on page 36). 

Danger Sense

You have the uncanny ability to sense the presence of foes before they reveal themselves.

Prerequisites: Wis 15+, Alertness.

Benefit: When you would ordinarily be surprised, make a wisdom check (DC 15). If you succeed, you may act in the surprise round as if you had not been surprised.

I'm aware there's a feat of the same name in Complete Adventurer.  I'm going to be supposing this feat isn't overwritten by it. 

Alertness comes free with a familiar or psicrystal, so some people could take this without wasting a feat.  The wisdom requirement is bothersome for most of the classes that get those though.  Techno gnomes (Dragon 320, p86) get alertness as a bonus feat, which would open up some other options. 

I'm having trouble figuring out how to guarantee a 15 on a wisdom check.  The only thing I've come up with is the aura of perfect order stance, but that's kind of restricted and high level. 

[SorO_Lost]

Marshal 1 / Charisma Based Caster 19
Makes DC 15 Wisdom Checks on a 1.

[Mithril Leaf]

A level 20 anthromorphic bat cleric could do it if he maxed out wisdom. Which he's doing.

[Tr011]

When your character is not being threatened or distracted, you may choose to take 10
(...)
Ability Checks and Caster Level Checks
The normal take 10 and take 20 rules apply for ability checks. Neither rule applies to caster level checks.

When you are surprised, your enemy will often not already be in melee and thus won't threaten you. But being rushed or not is within your DM's discretion. Anyways, if you can get the ability to take 10 regardless of that, you only need a +5 to wisdom checks. Unfortunately I don't know how to do this.

There is an item in the Miniatures Handbook that grants +5 to Charisma-based skill and ability checks. If you use the formula for this, you might get a +X wisdom-check item for 500gp*(X^2). But since that formula is kinda imbalanced I'm not sure if you can talk your DM into it.