Are there any servers with a working costume system?

[Rimenence]

Preferences:

• Rates: Greater than 1000x but less than 10,000x
• Max Base Level: 200 ~ 255
• Max Job Level: 120
• Max Stats: 200 ~ 255
• Population: At least 50 non-vendors
• Server Location: Preferably SEA. Willing to try NA though.
• Language: English
• No Third Jobs
• Working Costume System
• Preferably No Wing Customs. But this is not a deal breaker.

[D14]

You can try LegacyRO.

Rates: Exactly at 10,000x
Max Base Level: 250
Max Job Level: 70
Population: 70-80 on, 40 vends
Server Location: Singapore
Language: English
Third Jobs are just costumes, the skills don't actually work (sorta like wedding suits)
Costumes are enabled with custom costumes as well
There are wing customs unfortunately, but people tend to hide them with their costumes

Just answered according to your preferences, I hope you give LegacyRO a try!