[sdiy] New SID Chips?

[MTG]

Maybe this is old news, I don't know. Someone has an Indiegogo campaign 
to remake the Commodore 64 (or emulate it I guess, but in the same form 
factor). They list multiple SID chips in the list of features.  I'm not 
a huge SID fan myself, but I wonder how they plan to make it?

"Multiple SIDs for stereo sound (6581 or 8580)"

https://www.indiegogo.com/projects/the-64-computer-and-handheld-console#/

GB