iPhone OS 3.0, using a Springboard theme from Cydia
Back in the day you could apply custom themes using Cydia! I forget what this theme was called, but I liked the look!
I wonder whatever happened to BtBx and Goalkeep, those were cool apps that just vanished.
Ah, Winterboard, that's what the theming utility was called! Don't remember the website though.
The theme could be an older version of Suave. Looks pretty similar. Or its a completely different one. Looks indeed pretty cool though.