Bickerton
Folding bikes have been a popular target for the innovative folks. The Bickerton used an aluminum beam as the main frame element, as a way to reduce weight. Curiously, it used a 16" rear wheel and a 14" front wheel. It seems like things could have been simplified by using a single size for both wheels.
The company is still around and maintains a web site:
www.bickertonportables.co.uk
Steve in Peoria