AMP Research– Horst Leitner (Mr. Horst Pivot) sold the FSR rights to Mike Sinyard at Specialized. AMP (a product design house) continued making cool automotive stuff like custom interior parts for Mercedes, etc. last time I looked.
Syncros – Pippin Osbourne (one of the founders) left the business when a customer in Canada became paralysed after a stem failed, and went on to co-found Banshee Bikes. Syncros later changed hands again, going to Ritchey Design Group.
Iron Horse – all ended in an accounting scandal / alleged fraud by the father/son owners, including a raid on the employees pension fund, and off-invoice stock clearances through an on-line retail store owned by the same family. Interesting reading on the US forums, from some understandably bitter ex-employees
Kore – co-founder Bob Morales did a deal with Riteway (GT) doing lots of OE business in the 90’s, but left the business in the in late 90’s. Its been relaunched several times with a wobbly product focus, but currently doing some good business on mtb side
KHS – very little prescence in the UK (no current distributor), compared to the 90’s where they did good business with their Montana mountain bike range made from True Temper cromoly steel.