- First of all, in that example I'd say you would not have the last comma. So it's:
Things like a, b, c, d...
Certainly in English people use that form in emails, for sure.
It is completely normal and understandable to use an ellipsis for unfinished, continuing, lists.
Note that one particular use is to strike a humourous note:
And here is my ex-wife Cindy. And there are my ex-wives Helena, Georgia, Audrey...
You are quite right that it is "not really correct enough" to use in a printed book such as a novel. I'm pretty sure I've seen it a few times in, say, popular novels by Tom Clancy. But you're right, it's "not very posh," so you generally wouldn't see it in literature. And it's generally too jokey for non-fiction.
I'd say you'd see it in magazines, certainly anything like Playboy or Wired. It would certainly be used (particularly for sarcastic, comic effect) in magazine articles in the UK, by, say, Jeremy Clarkson.
It is completely and absolutely 100% understandable as an "unfinished list" to any anglophone.
Just for the record it is used somewhat technically by mathematicians, computer scientists, when discussing ongoing series, etc.
I hope this helps give the feel!