You can change the skin name for the qListForm Rich Text Editor using ezEdit under Control Appearance tab or if you are set on a particular skin, you may customize the skin so only rich text field is affected. All the skin files related to Rich Text Editor can be found in the SharePoint WFE server 12 hives. For example, C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS\QuestSoftware\Telerik\Q22007SP1\NET2\RadControls\Editor\Skins. It is recommended that you make backup of the skin folder you want to customize before you make any changes.