Being able to control a PS3 from LinuxMCE would be nice.
Afaik itīs not possible since the ps3 do not implement a upnp/dlna renderer whic can be controller from external devices.
Neither does it have any form of socket communication that can be used to remotely control the ps3.
It should be possible to use the sone ps3 sdk to create an app that can act a a remote control server for the ps3 over tcp/ip.
Unfortunately the sdk cost a whole lot of money and you also need to sign your code to be able to run it on any ordinary ps3 unit.
Considering the capabilities of a ps3 and the upcoming ps3 slim this would be a really nice addition to lmce to use the ps3 as a output device for audio/video and have a remote Orbiter to control it.
The only way I know of to control the PS3 with lmce is by using IR. A UIRT and a cheap IR remote for the PS3 can get it done.
I'm guessing it would only work for media functions and XMB navigation.