Either support a pixel format that also hase an alpha channel (e.g. ARGB1555) or add a setting for page setting to define a RGB565 color to be used as transparent color.
This would allow for more flexible UI designs by just dynamically overlaying partly transparent objects.
I am now reviewing all of the Feature Requests, this will take some time, patience please.
Transparency with 1555 on the list from post http://support.iteadstudio.com/discussions/topics/1000058748