Alternative to the ten basic dragon species

[Scalenex]

Here's an evil dragon (probably NE or LE). He dwells in the desert and has camped his lair around a well used oasis (or river or other source) along a major trading route. The nearby town and travelers have to give him tribute or he won't let them get water. His human minions do most of the treasure collecting. Their job also is to police to make sure spell casters don't circumvent their master's demands by using create water spells. Occasional use of water creation for personal use is allowed (most of the time) largely because they can't enforce it very easily, but use of magical created water for feeding livestock or irrigating crops is likely to bring down the dragon's wrath.

Dragon Extortionist (Old, 450 years, Huge) CR 18

Str 27 +8
Dex 10 +0
Con 19 +4
Int 13 +1
Wis 15 +2
Cha 20 +5

24 HD, Spell Resistance 34
Base Attack +30, Secondary Attack +28
Fort +18, Ref +14, Will +16 AC 22

Fear/Breath Save DC 27, spell save = 10+spell level+5

Fire Breath: 34d8 (cone)

Bite 2 Claws 2 Wings Tail Slap Crush
2d8+8 2d6+4 1d8+4 2d6+12 2d6+12

8th level sorcerer
0th (6 per day) Message, Arcane Mark, Detect Magic, Detect Poison, Flare, Prestidigitation, Read Magic, Mending
1st (8 per day) Shield, Obscuring Mist, Ray of Enfeeblement, Silent Image, Magic Missile
2nd (7 per day) Status, Cure Moderate Wounds, Summon Swarm
3rd (6 per day) Windwall, Protection from Energy
4th (4 per day) Greater Invisibility

Abilities: Strong Breath Weapon: cone of fire 34d8 (3), Water Breathing (1), Tongues (1), Create/Destroy Water at will (3), Feather Fall (3 times a day) (2), Levitate (3 times a day) (3), 4 points to spare

Feats: Alertness, Multi-Attack, Power Attack, Cleave, Snatch, Blind Fight

Skills (189 points, 27 max): Listen 27 (+31), Spot 27 (+31), Search 27 (+28), Intimidate 27 (+32), Swim 5 (+13), Survival 3 (+5), Appraise 11 (+12), Diplomacy 4 (+9), Sense Motive 11 (+13), Spellcraft 11 (+12), Knowledge (local) 12 (+13), Use Magic Device 11 (+16), Concentration 13 (+14)

You'll notice that Terwyn has powers that can emulate blink dogs, Aqayish can control elements of the sea and the as of yet unnamed extortionist (though he prefers to be called The Master of the Desert) can fatigue people and create illusions (aka mirages), both deserty abilities. All my dragons emulate themes.

Most of my dragons select or are given a title relating to their role, the Storm Dragon, the Crystal Blink Dragon, etc. This highlights each dragon's story role and uniqueness. It's not hard to imagine rainbow colored Aztec inspired feathered serpent dragons in the jungles. (I like that concept but I can't figure out what's it's powers or story role would be and besides my PCs aren't near any tropics).