You could remove the shower arm, screw it into a 1/2" chrome plated 90 degree elbow and, using the correct length nipple, hook it up where the arm used to be. The shower arm will then drop down parallel to the wall and sweep out away from it at the bottom.
It doesn't get much easier than a slide bar unit. They can be attached to the wall with double stick, and you almost don't even need a wrench to make the hook up. They are also very convenient for all concerned. Whoever has to clean the shower will like the availability of the handheld, and if mom ever has need to be using a shower chair, the slide bar and and hand held are very convenient/.
The two ends of a shower arm are different lengths. If you buy a 6", 8", or 10" shower arm and screw the shorter end into the wall, the other end will lower the shower head to whatever dimension you purchased.
I'm 5'11" and the Mrs is 5' nothing. There are multiple showerhead kits that allow adjustment of showerhead heights with out doing more than replacing the existing showerhead with an adjustable showerhead.
But, this is pretty much what I need. I don't know if I'll have the proper clearance if I were to buy a 10" or 12" arm and put the short end into the wall since the ceiling is relatively low and the shower line is pretty high already - I'll have to measure it...
There are hinged shower arms which allow you to postion the head at any elevation you want. If you get one, be sure it has "teeth" to hold the position. The ones that use friction are almost impossible to tighten enough to keep the head from "sagging".
if it has teeth, you will usually see them where the two pieces rotate. As as sidebar, I have made BN finishes by rubbing a chrome piece with a steel wool pad or open grit sand cloth.