Good prestige classes for a trap and construct focused "tinker gnome" type kobold?

[Rakaydos]

So, I have a concept for a "Tinker-kobold" who is an artificer//Sorcerer, but I havnt really messed around with arcane casters much. Are there any standout prestige classes I should look out for, and tricks and notable homebrew I should be aware of?

[Gildedragon]

There is the renegade mastermaker where you make yourself into robobold

With artificer Cha isn't the strongest choice, so there might be little sorc-artificer synergy (though there is kobold synergy via dragonwrought -> greater rite of something i forget at the moment, which is a +1 to sorc level)

A psionic class isn't a bad choice; psicrystals can be handy, and you get a different set of tools to work with while making magic items...

High elemental binder has a couple cute temporary magic item creation abilities along the elemental binding options presented in MoE and ECS

[Biffoniacus_Furiou]

Effigy Master, Complete Arcane. Note that effigies of a templated base creature cost the same as one of an untemplated base creature. For example, an Advanced (9 HD, Large) Fleshraker Dinosaur Effigy costs the same as an Advanced (9 HD, Large) Half-Dragon Paragon Fleshraker Dinosaur Effigy.

[Diovid]

Is sorcerer set in stone? Because you might want to go with something like artificer // rogue / trapsmith / combat trapsmith / Exemplar 1. Rogue also helps artificer more than sorcerer I think in terms of class features, a good reflex save, good amount of skills and skill points and so on while sorcerer 'just' gives you spellcasting which you already sort of have. And that's besides the fact that the sorcerer uses cha and the artificer uses int.

For the rogue use variants like Quick Fingers (Dungeonscape) and the Kobold Rogue substitution levels (http://www.wizards.com/default.asp?x=dnd/ex/20060106a&page=3). You could possibly use Martial Rogue (http://www.d20srd.org/srd/variant/classes/variantCharacterClasses.htm#rogue) if you aren't interested in sneak attacks.

If you want to create mundane traps take a look at the Extraordinary Trapsmith (Races of the Dragon) and Apprentice (Craftsman) (DMG II) feats.

These are also good places to start when building a kobold anything:

http://www.wizards.com/default.asp?x=dnd/we/20060127a

http://www.wizards.com/default.asp?x=dnd/we/20060420a

You might as well be an Earth Kobold (http://www.d20srd.org/srd/variant/races/elementalRacialVariants.htm#earthKobolds), it's basically a straight up upgrade for a Trapper.