If you can weld ali, then you might want to replicate what I'm doing at present. You'll also need to be able to cut ali tube at accurate 45 degree angles and do some machining if you want to use the standard handlebar end weight setup. First I bought a set of these clipons and clamps off ebay:
http://www.ebay.co.uk/itm/360544410408
As you can see, they're from China, but quality is not bad. You'll need to run an M6 tap down all the clamp threads, and probably replace the allen bolts with stainless, but at £36 delivered you really can't complain.
Then I (metaphorically) threw away the supplied bars, and got the bars shown in the picture below made up:
As it happened, I couldn't find anyone that stocked 22mm x 3mm wall thickness ali tube, so had to be satisfied with 7/8" x 10g tube. This is close enough on o/d, but has a greater wall thickness, and if you want to use the existing bar end weight arrangement, you will need to get the internal diameter of the tube machined out to 16mm in order for the internal bit of the bar end weight to fit. You'll also need to get the last 20mm or so of the bar end tapped to M18 x 1.5.
Mine are now just about to undergo polishing and anodising, so will hopefully be fitting them in a couple of weeks or so (depending on turnround times).
You can of course play about with all or any dimensions. If you want higher bars, just make the 45mm measurement 60mm or 90mm or whatever. As it stands the bars are slightly higher than standard - probably about 20-25mm higher and further back than standard. This is with the clamps under the top yoke, I hasten to add.
This design also reduces the overall width of the bars by an inch or two. This was important for me as I have to wheel the bike down a narrow passageway and I was sick of scraping the bar ends. You can also swivel the bars to change your preferred position.
