I know you essentially said "mod at your own risk," but using the following skin code for the radio_player.skin moves the buttons around a little and adds the radioart.
Code:
MEDIACAR Skin
MEDIACAR radio_player Skin
radio_off.png,radio_off.png,radio_on.png,radio_off.png
L,517,356,43,29,255,255,255,18,"ISOCPEUR","=ADD","CENTER"
L,615,356,43,29,255,255,255,18,"ISOCPEUR","=DEL","CENTER"
L,590,280,45,29,255,255,255,18,"ISOCPEUR","=SCAN","CENTER"
L,422,354,45,29,255,255,255,18,"ISOCPEUR","=EDIT","CENTER"
B,495,336,87,65,"ADDPRESET",
B,597,336,77,66,"DELPRESET",
B,571,260,86,64,"SCAN",
B,395,336,86,64,"EDITPRESET",
B,703,405,102,78,"EXIT",
B,601,404,100,78,"SHUFFLE",
B,501,404,99,78,"PRESETUP",
B,400,404,102,78,"TUNE",
B,300,404,99,78,"PRESETDOWN",
B,199,404,100,78,"MUTE",
B,96,404,103,78,"VOL-",
B,-2,404,98,77,"VOL+",
B,695,-3,106,72,"SKIN",
B,579,-2,114,71,"LAUNCH",
L,669,252,121,65,255,255,255,32,"DS-Digital","VOLUME","CENTER"
L,688,356,108,27,255,255,255,22,"ISOCPEUR","TIME","RIGHT"
B,462,-2,116,71,"VIDEO",
B,347,-3,114,72,"GPS",
B,228,-4,117,73,"SIRIUS",
B,110,-5,116,74,"RADIO",
L,388,116,407,29,255,255,255,22,"DS-Digital","RDSTEXT",
L,389,78,408,29,255,255,255,22,"DS-Digital","RDSNAME",
J,392,160,169,163
L,573,168,219,65,255,255,255,48,"DS-Digital","FREQUENCE",
S,97,75,287,327,255,255,255,0,0,0,255,255,255,0,0,0,106,186,86,,18,"ISOCPEUR"
B,2,238,92,72,"FINEDOWN",
B,-1,166,94,70,"FINEUP",
B,2,311,92,91,"PGDOWN",
B,3,73,91,91,"PGUP",
B,1,-2,109,65,"AUDIO",
END