Are there good GUI builder for Perl GUI libraries, especially for WxPerl?
I would recommend simply using web-based interfaces for everything. If you went with this approach, you could even run a local (i.e. on a Desktop) web server for "standalone" applications.
In like manner, ActiveState decided to focus on Web-based development instead of continuing work on their GUI editor
wxDesigner is the only one I know. I have never used it though.
Check out wxformbuilder. You can design your GUI there and generate an XRC file which wxPerl can then be configured to load.
It's still fairly new, but the Padre editor has an in-development Padre::Plugin::FormBuilder plugin that takes a wxFormBuilder project file and generates pure-Perl dialog classes.
Of the GUI editors that I have tried briefly, wxGlade seems the most natural to use, but it still doesn't seem to have the "drag and drop" functionality that I grew to love when working with Java in Eclipse or Netbeans. Don't get me wrong, I love Perl, but would still really like to see a nice WYSIWYG GUI editor.
For Wx:
For Tk: