Steve, I suspect your users are very similar to my users. Sometimes they're not quite ready to accept something, but if you pitch it to them the right way, they'll warm up to it really quick.
For example, you and I know that you can geolocate my ISP to Nagoya with an API call that won't take a milisecond. How about, instead, doing some JQuery magic:
"Asking Google for your location..." (2 seconds)
"Searching for apartments around you..." (2 seconds)
For a second, I thought "wow! another HN reader in Nagoya!" then I realized it was you. ;)
I think one of the problems JangoSteve had with his implementation is that people really don't like to see forms already filled in on their website (we've gotten a lot of complaints about it at our work as well)
I really like the solution that was shown in the related article. All of his Geolocations have a regular text section that says something along the lines of:
"Ship something from _San Jose, CA_. (Not in San Jose? Click Here)"
Which would then (I assume) replace text with a fill-in form using JS.
That would keep the "Why is there information in my form!" support mails down, while at the same time providing the GEOfunctionality and an easy way to correct mistaken information (Porn sites always think I'm in Kasugai, which is about 50km from where I live grin)
And be sure to save their inputted area in a cookie, so they don't have to re-correct your geocache every time they see your site!
For example, you and I know that you can geolocate my ISP to Nagoya with an API call that won't take a milisecond. How about, instead, doing some JQuery magic:
"Asking Google for your location..." (2 seconds)
"Searching for apartments around you..." (2 seconds)
"Picking best apartments..." (2 seconds)
$("precalculated-results").show();