I forgot a changelog entry for my patch, here it is:
2007-05-11 Ole Arndt <ole <at> sugarshark.com>
* slime.el (slime-select-buffer-function): New customization variable. (def-slime-selector-method): Use slime-select-buffer-function. (slime-recently-visited-buffer): Optionally find visible buffers as well. (def-slime-selector-method ?l): Find visible buffers if slime-select-buffer-function unequal 'switch-to-buffer (def-slime-selector-method ?e): dito
Schönen Gruß, Ole