I accepted
refi following consideration in
this thread and
reno in
this thread.
In both cases, there was evidence of usage in general news articles, and a few dictionary listings. Since we first looked at
refi it has, if anything, increased in usage in US news media, thanks to its relevance to mortgage debt problems.
It seems to me that, as RM surmised,
relo has not spread beyond the real estate profession to the same extent as the other two words. I didn't see it in any general dictionary, though it is listed in
The American Heritage Abbreviations Dictionary at
Dictionary.com and the
Double-Tongued Dictionary, which has mainly new words.
(It's also listed in Wiktionary, as Australian slang for a relative, but this word is more often written with a double
L, presumably to convey its pronunciation, rhyming with
yellow.
Rello and/or
rellie, or perhaps their plurals, might well warrant inclusion, but that's another story.)
I don't think
relo, in the relocation sense, is used at all in Britain or Australia. In US newspapers, it seems to be used infrequently, and when it is used, it's often put in quotes, as a term that is likely to be unfamiliar to readers. For example,
Super Agents, Super Teams in the
NY Times, 4 March 2007:
At the weekly team meeting at Michelle & Company, six women come and go, talking of corporate “relo.”
So at this stage, nineoaks, I feel
relo is not widely enough used.