Imagine doing with the BAC 1-11 something like what the Russians did with the Tupolev Tu-134UBL to make a trainer for the Tu-160 bomber.
Enough people have messed around with Whiffing the Concord into a bomber, so maybe graft the Concord nose onto the BAC 1-11 and use that as a trainer for the Concord bomber variant.
There were also the BAC X-11 high bypass turbofan proposals that never made it past drawings and models. It would be interesting to see where those could go.