Is it really the convention to name a some-user class 'some-userc'? Eeeargh -- I can see it's sort of like the established -p convention for predicates, but there at least it'd be 'some-user-p' instead.
It's not a widespread convention because use of OO is not massively widespread.
I agree stuff like this is ugly, but use of annoying naming conventions in order to get an extremely practical implementation language (particularly a Lisp) is a trade off I'm happy to make.