Summary of homebrew races. Comments please :)

In the homebrew I am workng on most of the races live of huge pillars of rock, apart from the elves, who live in the massive swamps beneath the pillars. This is a summary of the races and the alterations I am thinking about. I would love to get some comments about the balance of the races in particular. I want them all to be ECL +0.
Particular things I would like comment on:
The balance of the new elves.
The balance of the new gnome ability.
Ideas for a 'half-ogre' type race I could adapt for the durn-an

Elves live in the festering swamps at the base of the pillars. They are less civilised than 'standard' elves. THey don't have the weapon proficiencies or secret door detection ability, but they gain woodland stride, trackless step and the one that lets them detect safe water and stuff (can't remember the name).

Humans and Kuba (halflings) live together on top of the pillars. They are capable of interbreeding, so long as the human is small and the kuba large enough. The offspring is the same race as the mother. Kubai is their collective name. They can belong to one of the seven clans (from OA). no other changes.

The vanara live on the sides of the pillars, where they have managed to develop a kind of vertical farming community, with help from the gnomes and durn.

Gnomes mostly live in huge airships powered by all kinds of fans and jets and stuff. They have an inate ability to work with primitive machines and the like. They usually maintain small outposts on top of each pillar, known as 'smokes'. Instead of the illusion ability of 'normal' gnomes, they have the ability to duplicate 3 0-level spells and 1 1st level spell as machines. The spells they can duplicate are chosen at character creation time. Building a machine takes 1 day. It costs 10 gp per 'charge', pluys 100gp if it duplicates a 1st level spell. Once a machine has used up its charges it is useless.
Gnomes will have access to some kind of artificer PrC, as soon as I find one I like. The above ability is based on a quick reading of the Magic of Faerun book, which I don't own.

The durn are the 'dwarves' of this world. They come in two distinct subraces, which are not capable of interbreeding. The durn-ak, or makers, are like normal dwarves. The durn-an, or diggers, are a Large race, adapted to use their great strength to delve tunnels and mine for ore. I'm not sure what abilities the durn-an have. I was thinking of something like an ogre, but with minor light blindness. Ideas?
Some thoughts about the durn-an. I would like them to be an ECL +0 race, but I could live with +1.

Large size.
As well as the benefits and penalties for size,
+2 Str, +2 Wis, -2 Dex, -2 Int, -2 Cha.
durn-an are immensely strong, and their long periods of solitude in the deep tunnels make them thoughtful and wise, but they move slowly, both in thought and deed, and they are unused to the company of other, hastier, races.

Light blind. Don't know the mechanics of this.

Some of the usual dwarf abilities, especially stone cunning.

Favoured class cleric.
Another thought about the durn.

The durn-ak are not miners. THey use the raw materials mined by the durn-an to produce finished goods. So they don't get stonecunning, but get bonuses to several skills like profession(metalsmith) and the like.