Kobold Rogue Substitution Levels?

[Amoren]

What are peoples feelings on these substitution levels? They seem rather potent, trading in ~4 hit points and 1 skill point per level to get some huge benefits against traps (+6 search/DD against them, increased trap sense by one if you don't trade it for penetrating strike), faster getting away with withdrawling, and a huge mobility boost in return for improved uncanny dodge, provided someone is tossing around AoE against you.

On a related note, anything cool that could be done with just the craft (trapmaking) skill, or other skills, that'll make the skill point investment for the sub levels not as large of a cost?

[Diovid]

Personally, I like them.

I was thinking of doing a build along the lines of:
Kobold Paragon 2 / Rogue 3 / Trapsmith 5 / Combat Trapsmith 5 / Rogue +5

Using the 1st and 8th kobold sub levels and the quick fingers acf.

Then using feats like Apprentice (craftsman), trap sensitivity, extraordinary trapsmith, trap engineer and combat tinkering to maximize my trapmaking and trapfinding.

I won't be great since trapmaking is quite underpowered.

Edit: I would be using an Earth Kobold instead of the normal Kobold.

[Amoren]

Definately seems like something fun for a sneaky kobold trapsmither (actually, I just realized that he could use his own traps for the mobility. Set off an AoE trap that he can easily save against with a large radius, and watch him canon ball towards the unfortunate ranged target, hehee). Although I'm primarily asking for an assassin character I'm putting together, who's hunting down dwarves that slaughtered his warren. Of course, the bonuses to trap disarming would be great, but not exactly a core part of his build.