An official Palm online training guide shows the Palm Centro in a variety of colors, leading to speculation that Palm will release an unlocked version of the GSM Centro.
Palm released the Treo 680 in a variety of colors, so it's quite possible they will follow suit the Centro. This would allow owners to use the unlocked Palm Centro on any GSM network including T-Mobile here in the US.
The new colors as shown below include glacier white (with grey numeric keys), grey/black, ruby red and a navy blue variant.
