After reading some of the comments and thinking a bit, I changed my vote to "should be implemented with changes". I think an ability to change a comment into a post is okay (a button saying "Post as an entry instead" is okay) but if you want to link to the original entry, I think the onus should be on the commenter to add that html themselves (in other words, what you already have the right to do and what people expect you to be able to do). So the new behavior would just eliminate a couple mouseclicks, thereby sending you, along with your already entered text, to your "post an entry" page **without identifying the original source**, rather than potentially enable an identifiable crossposted comment that violates someone else's expectation of privacy.

Once you start thinking about this stuff, you encounter a slippery slope of privacy erosion, and even some hypocrisy, that you don't want someone to have the ability to crosspost the intensely personal thing YOU wrote, but you do want the ability to easily crosspost your own pithy commentary on someone else's private thought.

Maybe this is really just a can of worms. I think you should tread lightly, with great caution. Especially right now, when people are obsessed about their concerns and even slightly paranoid (me included).

Sorry, this was a little ramble-y written.