Italian maker Palazzani had a large range of TBL,s - first they slimmed the range down to three, now none (said to be temporary suspension?) Piccini built one but stopped, Eurocomach made a small one but finished recently. Italian machines above were all hystat with 4 equal sized wheels. Most of the small models had a low top speed. JCB in concert with Flannery are offering a free TBL operator course, perhaps a last ditch attempt to boost sales in the UK?
Granted there are territories where these things still rule, maybe they still have 'rebated diesel' to burn in them? Virtually never see one locally now.