<cffunction name="isEmpty" ...
regex that works when using "find" inside TM: <cffunction\sname=(["'])
bundle language text: { name = 'support.other'; contentName = 'entity.name.function'; begin = '(<cffunction\sname).(["''])'; end = '["'']'; },
If all you want to do is scope the name of the cffunction, I'd say you want to use a match/captures block, and leave the cffunction coloring consistent with the other cftags.
{ match = 'cffunction name="(\w+)"'; captures = { 1 = { name = 'entity.name.function'; }; }; }
It might be a bit much, but in theory it would work.
HTH, Daniel