Anything is possible, but why when you have a nice big button would you want that?
Basically for where ever you want the link, (public_edit_post.pl, public_pm_form.pl, public_polls.pl, public_new_reply_form.pl, and/or public_new_topic_form.pl)
Do this:
Find:
[/code]Below it add:(THIS IS NOT THE ACTUAL CODE, JUST an EXAMPLE!, read the comment about http text!)
</pre></div></div>For Example: in public_new_topic form.pl<br>Find:<br><br><div class="ubbcode-block"><div class="ubbcode-header">Code</div><div class="ubbcode-body ubbcode-pre" ><pre>
Below it add:
[code]
To delete the button, just remove the $spellcheck_button, course by doing this you disable the ability to turn it on and off in the CP. A better way would be to change the my $spellcheck_button code and then move the $spellcheck_button to under $is_ubb stuff, if you can figure out how to change the code there.
Now I have not tested this, but it should work.