You can actually remove the colorbar completely quite easy.
1. Run REGEDIT as administrator
2. Open HKLM\Software\Classes\Drive
3. Change the value for the key TileInfo. Remove the phrase "System.PercentFull;"
The key should read the following:
4. Restart windows explorer (open task manager, and kill the process explorer.exe, choose File, Run and type in explorer.exe)
5. Now open Computer to see the absense of the colorbars
Note: This method does not disable the warning which occurs when free space falls below 10%. It does only remove the anoying red bars.