Here is an easy way to make your own extended mirrors. This was a modification article I wrote for a CT110 group and I have just repeated that article. The photos make the whole process obvious but I have included the text as well.
"My CT mirror stems are too short to give me a clear view without leaning to the side a bit. Have looked for longer ones, but decided to modify the ones I had. Mine have 10mm stems, so the sizes quoted here would need to be adjusted if you want to modify mirrors with 8mm stems.
Materials: Aluminium tubing - 10mm outside diameter and 10mm inside diameter; 24hr epoxy.
Step 1: Cleave the mirror stems in twain. Cut two 50mm pieces of the smaller tubing, and two pieces of the larger tubing, the length of which needs to be worked out by trial as follows. The small tubing will be a spacer between the halves of the stem. The longer tubing will be slide over the stem ends and the spacer, and should be as long as the straight section of the whole stem when the three pieces are butted together.
Step 2: Scruff the stem ends and clean with solvent. Use quality epoxy for the next stage, not that stuff from the $1 shop.
Slow-set epoxy gives plenty of time for the job, and is much stronger than 5min epoxy.
Coat the inside of the longer tube, the stem ends, and the spacer piece with epoxy. Insert the spacer into the long tube
and push the stem ends in at each end. At this point there will be a hydraulic / pneumatic lock as there is nowhere
for the trapped air and excess epoxy to go. Drill a 1mm hole in the middle of the large tube and be prepared to deal
with the epoxy that exudes when the stems and spacer are butted together.
Step 3: The stem ends can rotate in the tube, so while the epoxy sets, they need to be held at the correct relative angle.
Both ends must lie in the same plane to reproduce the original positions of mirror and mounting. Below is
how I packed the mirror to do this.
Step 4: 24 hours later, just a coat of quick-dry low gloss enamel to go. See the tiny pressure-relief holes?
Step 5 : Spray stems with satin black enamel.
Done. Saved some bucks and got the satisfaction of doing it yourself. "