The good news is that iDBUS now offers coach services to Aachen and Cologne, but not yet from London. You can buy tickets separately from London to Paris or Brussels, then from these cities to Aachen or Cologne. Let's hope that this will change soon.
iDBUS coaches had begun operating on December 1st, so we give this information with a slight delay. Sorry :)
The new iDBUS services, Brussels - Aachen - Cologne and Paris - Aachen - Cologne, are now available in the booking system. The coach trip from Brussels to Cologne takes only three hours and 25 minutes and costs €19, while the trip from Paris to Cologne takes seven hours and 35 minutes and costs as low as €35!