Ideally I would also like to select the colour (internal and external) of
the Carcasss so that I do not have to have that "clinical brilliant white"
inside that a lot of units from MFi, B&Q and Ikea have.

MFI sell display cabinets for glass doors that are coloured throughout,
although there might not be a large choice of colours beyond white or
woodgrain effect.

Christian.