| You are absolutely correct with reference to s179 rules, a taxpayer may not use s179 on property that is generally leased to another party, but of course there are exceptions such as for Hotel/ Motel Industry.
With respect to the smaller items which have no definable useful lives, I would consider using the MACRS 7 years. In these situations, the IRS would prefer that the taxpayer use a reasonable useful life, and based on the small nature of these assets, in my opinion they would fit this particular type of asset class. | 
