I have bought a used pair of Origin 8 drop bar ends, the same as these.
http://www.sjscycles.co.uk/origin8-p...ack-prod18606/
Some time ago I replaced the Mezzo bars with shallow riser MTB bars and ergonomic bar ends. Being wider, the bars enable the bar ends to sit either side of the front wheel when folded.
I tried longer bar ends but they hit the front forks when folding, I am expecting the same to happen with the drop bar ends. So I think bhkyte is correct, I will probably need a QR stem to enable the bars to rotate out the way so the ends dont hit the forks and then rotate into a final more compact position. I wont really know until the bar ends arrive but I am thinking about getting a Dahon QR stem or modifying the Mezzo stem to be QR. I intend to keep the flat bar brake levers and shifters to keep the fold as compact as possible and I only tend to go onto the drops when cruising.
When the bike was setup as a standard I4 I did some experimenting with cutting up drop bars but then I realised that the grip shifter would not go round the curves. With drop bar ends that would no longer be an issue. Now the bike is dual drive its not an issue either but my main reason for going with bar ends is to get a wide spacing when used with the MTB bars so they will sit either side of the front wheel. The shallow rise MTB bars are approximately 59 cm from end to end.
Bhkyte, I dont think hammerite will be up to the job, how about cutting up an aluminium drinks can to use a shim? Be careful of the edges, they will be sharp so make the shim a little narrower than the width of the clamp so the edges are concealed.