Does anyone know if the Nong Khai imm office has started issuing 30-day extensions again WITHOUT having a return ticket home?

As far as I am aware no, they still require proof that you are existing via an air ticket within the next "n" days & will then give you (for 1,900 baht) an extension to cover you to the date on the ticket, up to a maximum of 30 days....

Are there any other offices in the region issue the extension WITHOUT the return ticket?

SP, it's going to be down to local discretion. You can but give it a try, though I'd have a contingency plan.

The last time I tried for a 30-day extension on a 60-day Tourist Visa in Nong Khai was in September '07 and I was refused and offered 7 days. He advised me not to bother and to cross the border which I did of course... I never tried again after that.

Plus, of course, at the moment they are giving double entry tourist visas (2 * 60 days) from Vientiane Embassy free of charge. So it hardly makes economic sense to pay 1,900 baht for an extra 30 days even if you do have a air ticket....

Yes, we've really come full-circle on this one. In the not-so-distant past, repetitive tourist visa
applicants were often treated as if they were committing some form of criminal act. NOW,
they can't even give the visas away free. Sorry, it's karma. Have to say BobHelm has
nailed this one down. Why even bother with the hassle of an ext. anymore. AND if you do just
cross over the land border, you will in all likelihood only get 15 days at current. As usual, the
different heads of this monster rarely seem to collaborate. Just try and roll with the punches.