Idea: If a player trains to lv5 in all skills within a category, they unlock a suit/modification specific to that category. Perhaps it's only the tier-3 category, or the highest category in a chain of dependent skills, or it could be smaller mods as they progress through the Skill Tree.
example: Atmo Pilots get something like a high-altitude flight suit. Space Technicians, one that looks like it has the jetpack and tools integrated. Atmo Technicians get a mechanic suit. Miners get rugged-looking, skuffed-up suits. Simpler mods within the tree could be pouches, utility belts and tools for skills related to working, armor for pvp-related skills, or fancier badges/trim for architects and space pilots, etc.
