My gnomes occupies the "wise, magical race" niche IMC. It is a niche often given to elves, but I don't think it fits D&D elves. I can't picture a chaotic race of eternal adolescents as wise. Magical maybe, why not, but then fickle and unpredictable and idle and easily distracted. Oooh, shiny! Wants it!
So, the wisdom niche is given to gnomes. You want to find an old loremaster who knows all the secrets of Earth and the Stars? Chances are, he'll be a gnome. The best loremasters are gnomes.
Gnomes are wise and benevolent. Not many are adventurers, and when they are, they try to look as irrelevant as they can, for they know their strength lies in their head, not in their arms or legs. This is a kind of humility -- even if some of them hide this humility behind buffoonish pride and ridiculous claims of grandeur.
Gnomes as bards? It could be OK if you ditched bardic music, modified the class skill list, and gave them an Int-based, prepared spellcasting from the sorcerer/wizard spell list. And ditched the alignment restriction, or at least replaced "non-lawful" by "non-evil".
No, but my gnomes are wizards. And/or druids.
I've house-ruled back in the gnome cantrips from 3.0. They cast low-level arcane spells, which are subject to arcane spell failure, and which requires to have at least Int 10. Not Cha-based spell-like abilities. As a result, this mean that each and every gnome (with at least 10 Int), regardless of his profession, can create alchemical items. This is one of the consequences I was looking for. All gnomes are alchemists.
As you probably know, alchemy is also a transcendental philosophy. The philosopher's stone, which turns metals to gold and grants eternal life, is a magical wonder, but also a metaphor for enlightenment. My gnomes have a strong affinity for alchemy, both the practical aspect, and the philosophical aspect. Again, gnomes are the wise folk of the campaign.
This lead to one of the most surprising aspects of my gnome. Guess which is the typical "elite combat class" for gnomes? Not fighter, not ranger or paladin, absolutely not barbarian... But monk. Gnomes are famous for their zen monasteries. As a whole, the gnome race is somewhat monastic, living a secluded, peaceful existence dedicated to the acquisition of wisdom, knowledge, and enlightenment.
In fact, IMC, "gnosis" is a word derived from "gnome".
If you want a tinker race, you'd have to go look to dwarves, who are famous for their engineers. Of course, the dour and grim dwarves are more noted for making large mills and similar utilitarian mechanisms than for silly explosion-prone contraptions. There are no silly explosion-prone contraption makers IMC.
Their physiognomy [no pun intented] is: short, stocky, with bulbous eyes and long arms that nearly dangle to the ground. At least, their favored class is rogue - not bard. They are friendly, cunning, stealthy, nosy, workoholic, and a little dense in the mind. Their game stats are unchanged.
