An independent programmer/developer at Smealum.net recently made a post on his blog detailing one of his projects; 3DS homebrewed apps and channels.
Just to give you an idea of what he is up to, he showed Pokemon silver on 3DS.
He posted a video showing him booting into redNAND mode on 7.1 from 4.2 (works on 4.1-4.5 ofc) and running a homebrew game within its own little channel, with custom icon and banner. He said:
This video is a glimpse at what I want for the up and coming 3DS homebrew scene, ie a way for people to make their own homebrew applications and install so that they’re directly accessible from home menu. This has a number of advantages over running code “on the bare metal” as some are already doing.
Firstly, the homebrew code will be limited to user mode code just like commercial games and apps, so it makes it tough for a code to accidentally bricking your code. Furthermore, it means that the code will be able to go up with every service of the 3DS’s operating system. Lastly, you get your own channel in the menu.
E goes on to tell what is required for that to be turned into reality. First, a away to create new channels and a way to install them. Right now, he is working on creating a channel through something called ctrulib. His work already takes care f the basics like interactions with the NS and the HID mode for input.
The second part, installing the channels is something that has no public method at the moment. So even after compiling something like ctrulib you will not be able to run it. He says that once his installer is ready, the next big step will be taken.
Smea insists that he will have the installer ready by the next couple of weeks without specifying a date.