I am seeing the prompt "Looking for local results for ..." and an input field for a location or postcode here in Australia. I rarely search for single words but I got this with the word "mattresses" and later with "pizza".
This was discussed last year in this thread [webmasterworld.com], but not the search customisation mentioned by rustybrick here [searchengineland.com].
I chose not to tick "Remember this location" and this could explain why my subsequent searches weren't locked to the postcode I typed (not my physical location). Anyway, the SERP looked almost identical to the default, so I am not sure what to expect. Perhaps the test is to see how many people use the option?
I'm seeing the same thing here in the San Francisco Bay Area.
Behavior is not consistent on single or multiple words, or on singulars and plurals, btw. Also to take the liberty of using specific examples, [hardware] doesn't return the location input field, nor does [hardware store] singular... but [hardware stores] plural does return the prompt and the input field (which then leads to map results).
I'm seeing this in the UK now too. It appears that it's restricted to influencing the 10-pack - no rankings are changed in the web results. It'll be interesting to track how this changes, as I suspect that the broad category matches will get more granular over time.
Oh, I forgot to say that adverts could be being matched against the location entered - but the poor location awareness of UK ads in general make it tricky to be sure (this is also made harder by the broad matching options selected by advertisers).