Mp3 player HU interfaces, only IPOD ones?

[Hate]

I want to buy a large portable mp3 player soon with intention of plugging it into a suitable HU to control it like a CD changer.

so far, all I can find are iPod interfaces.

do other manufacturers support such a thing or am I stuck with ipods?

 

[Hate]

ipods may be fantastic but

a) battery life
b) i use linux
c) itunes

are my reasons against

 

[Hate]

yeah, but I may just as well stick with MP3 CDs if i'm gonna do that, cheaper