Custom UI for adding webpart in SharePoint

1. I don't require default webpart adder provided by SharePoint.

Instead I require a customized UI(With Categories as DropDown, Webpart Preview Images and it should appear on left side of the screen, etc...). Does WebPartAdder class support customized UI?

2. Assume, I am developing a custom control to achieve webpart addition, how should I make my custom control to open, whenever webpartzone(Add a WebPart) is clicked?

Thanks, B.J.Prasanna.