I recently made my first OXID eShop module: OXID-manufacturer-text-mod
Which basically adds a long description field to the manufacturer.
This comes just as a normal textarea, as usual in OXID CE.
If you would like to add an Richtext Editor, you can purchase the fck Editor module
and install it, if you did not already.
After you installed the fck module your textareas of the basic shop are rich text.
But since the manufacturer long description comes from the module, you have to teach the fck module the new field.
Unfortunatly we cant extend the fck module, due to some private vars & methods.
So we have to hack it, like so:
const MANUFACTURERS_MAIN = 'oxmanufacturers__extlongdesc';
self::MANUFACTURERS_MAIN => 'editor_oxmanufacturers__extlongdesc',
Then enable the module for the manufacturer text in the modules section of the backend:
manufacturer_text => tc_fckeditor/tc_fckeditor
And you should be able to rich edit your manufacturer long description.