OK - tell me if this is useful. I created a DNS list that you can pass a
host name to and get information as to where the registrar barrier is.

You can use it as follows:

dig .rb.junkemailfilter.com

dig perkel.com.rb.junkemailfilter.com - returns
dig perkel.co.uk.rb.junkemailfilter.com - returns

If it's a single level domain it will return
Two level domains return
Three level domains return

I'm using it for some statistical stuff but I'm wondering if anyone else
finds this useful. Thinking about using it to forward spam to
abuse@ to report spam.