Have a look at this:

http://www.blog.uofmtiger.com/2008/01/0 ... erfection/

Seems to be a SlimServer solution. Haven't tried it yet.

Would love to see a similar looking UPnP remote control for the iPhone/Touch (or something looking like iPeng / normal iPod UI).

I am running SqueezeCenter 7.0 beta now with the iPhone skin from iPeng. It looks good, but I would have preferred being able to run it against the Firefly server instead as it is considerably faster and has a (to me) much better interface on the Sondbridge itself.