Why not use Roman numerals? Easier to implent (since you would only need I, V, X, L, C, D or M.. though doubt someone will reach over a 1000 rebirths) for the coders.
Roman numerals:
- I (1)
- V (5)
- X (10)
- L (50)
- C (100)
- D (500)
- M (1000)
Display location: right behind your Lv. display when you press TAB.
Example; Lv. 98 (IV) meaning this person rebirthed 4x, and it still could get a colour per 10 rebirths.
Example colours for about of rebirths:
- White (0-9 rebirths)
- Yellow (10-19 rebirths)
- Green (20-29 rebirths)
- Blue (30-39 rebirths)
- Purple (40-49 rebirths)
- Red (50-and above rebirths)