I (humbly) suggest
Heroes Against Darkness, which seems to cover off most of what you're after:
• IT'S FREE!
• It's self-contained (single 230 page PDF)
• Martial powers and spells go to Level 10 but they never become obsolete, so higher level play is supported
• Separate race and class
• Combines the best aspects of Basic, AD&D, 3rd Edition, and 4th Edition into a single modern system
• It's a neo-clone, not a retro-clone!
There's a thread about it here:
http://www.enworld.org/forum/genera...against-darkness-neo-clone-released-free.html
And here's a bit of a blurb about the game:
Imagine an ancient world torn apart by primal powers. A place where magic runs through all living things and erupts from the minds of powerful magi, where humans, elves, dwarves and orcs walk the same earth, where ancient gods fight side-by-side with mortals in an endless battle between order and chaos.
Adventure is everywhere. This is the world of Heroes Against Darkness.
Heroes Against Darkness is a free, fast, flexible, and fully-featured fantasy d20 RPG system. The game is quick to learn and play, while offering progressively greater options and flexibility as players develop their characters and explore the breadth and depth of the system.
For Players:
• A game that’s fast, fun and deep
• Streamlined rules system using unified mechanics
• Eleven character classes for all play-styles
• Three martial classes: Warrior, barbarian, berserker
• Two specialist classes: Rogue, hunter
• One hybrid class that combines magic and martial: Hospiter
• Five magi classes: Warlock, healer, canonate, necromancer, mystic
• Extensive character background and skill options
• Fast character building with plenty of depth
• Martial and specialist classes get meaningful combat choices through class-specific techniques that are based on trade-offs and the unique capabilities of each class
• Anima points-based magic system with five main schools focusing on each of the following; physical, healing, protection, necrotic and controlling
For GMs:
• A system that’s easy for the GM to set up and run
• Intuitive and clear rules
• Set up unique combat encounters in minutes
• A simple ability test system for non-combat challenges
• Support for long-term campaign play
• Extensive GM’s Guide to help run the game
• Huge bestiary with over 80 monsters
• A framework for quickly making custom monsters
• A comprehensive world-building guide
• Appendix of key tables for GMs