yes, it's hard.
Once a game is running, the running code belongs to the game as well.
So basically, all you can do is patch the game return to menu code so that it loads a channel instead of the system menu.
Most usb loaders have such a feature for backup's of wii games.
I don't think I have seen it for VC and Wiiware. I guess the method for doing things would be pretty much the same.
Homebrew emulators and games usually either return to the system menu, or to the homebrew channel.
I am now working on a method to have them launch a specific channel instead of both other options, as the system menu isn't very fast in neek2o (So I prefer to avoid it when possible), and the hbc 1.08 isn't working in neek2o environment.
If I modify the homebrews for neek usb acces, I might as well add the return to channel feature as well.