I am going to the LHS tomorrow to consider some HO sized bottled gas tanks to put outside a home and office. They are small enough that they would look to be the right size that somebody might use to supply gas for a kitchen stove. I would prefer that they stand upright rather than extend horizontally but I can't think of any alternatives. I almost bought a S scale oil tank because I though it would fit and look good on my layout but fortunately spotted a Lionel elevated oil tank with light that seemed to fit the bill a little better.
What items (if any) of other scales have you incorporated on your layout? (I do not mean to include aircraft hanging above layouts with this question as I recognize that many use 1:72 aircraft, etc.)