"Yob" is of course current here - more so than ever perhaps. Doesn't exactly means "boy" now, but more "lout", and there's no shortage of them. I can't off-hand think of any more examples in present-day use.

That doesn't mean there might not be some - the thing about slang, whether backslang or rhyming slang, is that it tends to just merge into the language, so that people never think about it in those terms.

There's a couple of sound files on this link with a Liverpool version of backslang.