Seems to be working fine now. I was using a DirtCheap DID, but whilst re-configuring my Obis in preparation for the demise of XMPP, I reinvestigated - and to my delight, I find that Callcentric "free" DIDs now properly receive correct CallerIds from Google voice.
IMO the most economical and powerful solution to XMPP being dropped is
GoogleVoice ==> Callcentric DID for inbound
and
LocalPhone.com (with my GV number "spoofed" as the callerid) ==> for outbound
LocalPhone offers outbound calls to the US for prices from $0.001 to $0.005 / minute, depending on your subscription (or not) to a bundle of outbound minutes per month. (I prepay $1.60 for 800 minutes)
For my purposes, this works out even cheaper than the plans OBIhai is promoting.