hardware supporting autoplay mp3 on startup ?

[_ben]

Hello,

I want to link the alam detector for my house to an audio player playing a song (my voice recorded in an mp3) when powered on. With that I can "simulate" activity to burglars.
I'm very surprised that there is no solution for that in the market.

I've read in the RockBox manual that the Rockbox firmware supports "playing a song on startup".
I believe I can connect the hardware with the adaptator to an electrical outlet, and make the song play and stop when powered on/off.
It's important not to require additional action as I am not at home when playing... I don't need any other function.

Could you confirm me all the hardware listed in the stable ports support this function (see main page http://www.rockbox.org/) ?
Could you give me the cheepest one ? 

I have been searching for days without success...

Thanks uo very much for your help,
(please excuse my english, I am French)

Regards,

Ben.