Started working on this myself last night -- since my PI3 finally showed up.
Did not have any problems getting attractmode to compile and run on the default raspian image provided on the NOOBS
card that came with my PI3....(using the instructions I found on this forum).
Biggest divide right now is that most of the "pre boxed" pi emulation scene is dedicated to framebuffer setups (like RetroPI) to avoid the overhead of X -- and attractmode requires X.
Would be sweet to have an out of the box process like RetroPI that included attractmode as the default FE....Since it is so much prettier and more flexible than EmulationStation.
Personally, I have not had any issues running any of the pre compiled emulators inside of X --- but I am dead set on having a clean (up to date) Retroarch/Libretro implementation with all working libraries, that is front ended by Attractmode. Don't really have the time to wait 24 hrs for everything to compile itself....
Was almost there last night until I realized that RetroPie uses emulationstation to handle controller config and have somehow disabled RGUI (at least I could not figure out how to invoke RGUI on the RetroPie retroartch binary to manually configure my gamepad like I normally would with all other RetroArch implementations -- and did not have enough time to manually add the cfg's for my gamepad).....So I am stuck there for the moment.
Tonight I am going to go just opposite, and try to install the RetroPie image and get everything configured and running -- and then turn off Emulation Station -- and then install X and then try to compile and install attractmode on the retropie image itself....That to me would be cleaner (and more lean) than what I tried last night.