Recently I was asked if multi-outlet surge protector extension cords are legal as a permanent power source. My initial reaction was no since they are still an extension cord, but I can't find the section in the 1997 NEC that applies. Section 240-4 doesn't address this product.
Here's a start. 210-50(b) says that a receptacle outlet shall be installed wherever flexible cords with attachment plugs are used. I looked under 400 (Flexible cords and cables) and noted 400-7(b) which requires cord and plug appliances and equipment to be energized from a receptacle outlet. Looking under "receptacle outlet" and "receptacle" in definitions of Art 100 we see that they are talking about receptacles on a yoke..which pretty much rules out your power strips. There is some language in 410-56(g),that actually pertains to the context of fixture wiring but might be repeated somewhere else in the Code, that: "No receptacle shall be installed so as to require an energized attachment plug as its source of supply."
Take a look on the back of the strip. chances are that is says the word 'Temporary' somewhere, which would probably also be a condition of it's UL listing.
These things are used extensively around here. The Fire Depts here don't seem to consider them an extension cord, as they don't write them up in their inspections. As a "temporary", does that mean they must be unplugged and plugged back in once every 90 days?