We are developing a new AddOn for SAP B1, but we want to use it integrated in SAP B1 and without integration. Is possible to develop an AddOn with the look and feel of SAP B1, but that doesn't run in it?
AFAIK, there isn´t any class or library that helps you to create windows forms that look like B1 forms.
What we have done is get the form header and minimize, maximize and close buttons images, and paste them in a form without borders and control box. Then we have use some code to control this buttons behavior, and the form movement when the upper bar is drag&dropped.
On the other hand, have a look at this tool if feeds your needs: