Thanks very much all!
The 4chan data comes from the json api of archive.4plebs
http://archive.4plebs.org/_/api/chan/search/?tripcode=ITPb.qbhqo
The non-trip posts I gathered by searching for all the confirmed IDs.
The 8chan data is from the json interface of this site. I.e. if you change 'html' in the url to 'json' you will get the json source of this page.
Then I transform both json formats into something uniform and build a little interface around it.
Mailto: I already did, it's red-brownish, the other things are now implemented.
I'm sorry, I use modern Javascript which doesn't work on IE or Opera.
I reformatted the date to "Dec 11, hh:mm:ss"
I don't feel sweeping through all boards is necessary, but I can do it for some time to see if I get any extra results.
I'm now working on integrating Spreadsheet anon's results into this web-app to have some answers available as well.