Hi! I've forked named-readtables and removed the kludge which alters swank:*readtable-alist*, pull request is here:
https://github.com/melisgl/named-readtables/pull/8
and an appropriate pull request to SWANK:
https://github.com/slime/slime/pull/278
Start of the discussion can be found here:
http://thread.gmane.org/gmane.lisp.slime.devel/11574
With best rgards, Budden