Good subject to entertain--thanks for mentioning it.
Although your ideas have merit I checked several of my Electrolux manuals and did not find any specific directions for storage in the older manuals except how one could store the attachment Companion (for the Model XXX or Model LX).
Here is what a Model 1205 manual states:
"Always stand the Cleaner on its storage end with wands beside it. Avoid bending hose sharply by hanging it over two clothes hooks spaced about a foot apart on the closet wall. Power Nozzle will stand with handle upright or may be hung on hook."
Although something to think about, too, is that a company will benefit from the sale of new parts if the old ones wear out from lack of customer care, so I think you are wise to be proactive against brush and belt deformation.
In addition, I would think if a vacuum cleaner were going to be stored for a long time without being used it would be a good idea to empty the cloth bag or dispose of the paper bag if it contains refuse. Mouse-proofing would also be a consideration for tanks by covering up the suction and blower openings and removing the cloth or vinyl outer bags of uprights--particularly if they were stored in a garage or shed. Also, dry and cool environments would be better than humid and hot ones if there is an option.