There are several launchers available in Play Store (Nova, Apex etc) but they're primarily designed for phones. A thread on Freaktab has a download containing 7 launchers designed for TV boxes. They've been extracted from other TV box firmware:
http://freaktab.com/forum/tv-player-support/rk3288-devices/17935-tv-box-launchers-rk3288
The download link for the launchers keeps changing but the current one is:
https://mega.co.nz/#!DV0RzbII!ar2YXP0Z3LQKOdDQYuP7wAB6NWYJlmoycfDkMutAtzE
Of these launchers all but one will install on the Q5/Q10/M3. Most have a few features that won't work on the HiMedia boxes due to missing apps, some have lots of this. Of the 7:
HPHLauncher - Installs OK! - Pretty to look at. Works OK.
LauncherSigned - Installs OK! - Simple and not great to use.
LauncherRainbow - Installs OK! - Nice to look at but loads of menu items don't work.
SunUI - Installs but won't run!.
Lighthome - Installs OK! - Same as LauncherRainbow.
M8Launcher - Installs OK! - Similar to Xtreamer Prodigy launcher. Lots of menu items don't work.
XHHome - Installs OK! - RUI launcher. Also available here: http://www.uprui.com/en/cp3.htm The best of these launchers. Usable and simple.
If nothing else it's interesting seeing what other launchers are like.!
If anyone has any other launchers feel free to post them in this thread.