I'm an expert with Tcl/Tk and Perl. I have made several user interfaces with Tcl/Tk during the last fifteen years, from small games to an alarm application user interface for a security company. I do not have rights to that content so I don't have a portfolio.
I have been programming with perl for over fifteen years too. I first started with CGI-scripts and recently have been doing code and configuration generators. Basically reading data in various formats, interpreting the data and outputting it in other formats.
I have never coded a line using Perl::Tk or Perl::Tkx, but that's just Tk- and related libraries in another syntax. I think my experience with Tcl/Tk itself is more important than experience with the perl counterparts, because they are just wrappers around the same library. I guess I could have just left that out, but I prefer being open, honest and transparent about everything.
I'm not a visual designer, but I assume what you need is just a standard application UI. I do have education and experience in usability, so if you need an opinion I can give you one. :)
If you decide to choose me, I'm flexible, but prefer to work in few long stretches and then have a break instead of an hour here and an hour there.