Hi Don,
Interesting stuff. Just before Les died he was working on a brand new design tape echo unit using mellotron width tape. Sadly it was never completed and we haven't had the time to resurrect the work. We have the sketches somewhere as I did see the design work but it was only at the paper stage. The idea of an integral unit needs careful thought nd the time to ponder. Sadly we have neither just now.
Best,
Martin