[asterisk-dev] "system" telephones for asterisk

[Wojciech Puchar]

i was asked by client if it is possible.
i use asterisk for a long time but have no idea about this.

I mean telephones that

a) have lots of extra keys. What IP telephones can provide this - i mean 
pressing extra key will be recognizable in dialplan
b) leds that shows what "lines" are busy or not. Are there any telephones 
that supports it with asterisk?