Hi Bruno
I'm going to respond to the part of your question about Moodle.
There are a few ways of making Moodle more graphics rich, but like any visual design you need to consider the impact - images can add interest and clarity, however they can also confuse, clutter and give inconsistent messages (both in terms of purpose and quality).
At FLiT we have a visual format that we have designed for fully online courses such as the Diploma in Business and the Creative Industries Training Schemes. This involves the use of colours and icons to separate activities. If you'd like to see a working example I can arrange this.
Otherwise if you'd like to have a chat with myself or Paul Devine, I'm sure we can help you with other solutions.
Cheers, Craig