The 12V/120V wiring harness from the chassis to the largest flush floor slideout on our QSDP is supported by a 2" wide x 1/8" thick x 48" long nylon or similar material "ribbon" strip spanning a distance of 38". The ribbon-type support is attached at each end by a small steel plate 2" x 1 1/2" screwed to the respective walls of the chassis and the slideout. The support of course flexes each time the slideout is extended and retracted, with the weakest points at the place of attachment at each end. I have repaired a broken support at each end twice so far simply by shortening the ribbon and reattaching with the existing steel plates. The infamous support has now broken in the center (the next most vulnerable point) as well as developed a partial break at the slideout end.
My options are:
1. Reattach the slideout end as before and patch or overlap the center break fastened with bolts or rivets. However, the length of the ribbon support is becoming compromised.
2. Locate and purchase a replacement support of the same or possibly more durable material and recreate the original configuration.
3. Determine if a new and improved method of supporting the wiring harness is available and practicable.
Your learned advice and assistance will be much appreciated!
FWIW, one other slideout has the same type of wiring harness but it is servicing a short slide with a 20" span and has given me no grief, so far at least.
This is the wiring harness viewed from the rear of the coach:

The remaining pics are viewed from the front of the coach.
Attachment at chassis end:

Attachment at slideout end:

Close up of attachment at chassis end:

Close up of attachment at slideout end:

The middle portion of the wiring harness showing the break in the center between the two zip ties, buried in the large outer and smaller inner wire looms: