I spent some time checking out PLT and I do think there's a lot there.
What I'm kind of excited about today is the prospect of using SISC. I really want to do something with Java, because I want to be able to say that I have and I need a project. For Web Automation, I should be able to pull in The Jakarta HTTP client, which looks excellent.
One thing I was judging Scheme environments on were the quality and maturity of their HTTP client API. I didn't find anything too exciting out there after being spoiled by LWP in the Perl world. I think the Jakarta HTTP library will be darn close to LWP and SXML will be a natural for what I'm planning on doing.
I'll keep you posted