Personally, I would make the trade with or without an extension.
But, I am probably an extreme minority.
I am with you in that 'extreme' minority and here is why:
As a GM in any sport, any move you make comes with risk. I think this is a move Danny should make with or without the extension and here is the thought behind this.....
We trade for Chris Paul and immediately become better offensively, something this team struggled with mightily last year. Once Paul is here, Danny, Doc, The Big 3, etc. have a year to convince him into signing the extension along with the fact that Paul comes to an organization that players, once here, grow to love. You hear nothing but positive things from players that have played for the Celtics organization and I would think that Paul could get wrapped up in the history and prestige that comes with the organization after being a part of it.
There is also the Howard situation. You can't tell me players don't talk about this kind of stuff and I know for a fact they do (ala Miami's Big 3) so with Paul now in Boston there is not only The Big 3, Doc and Danny convincing Howard to come but also Paul and all that put together has to be enticing to Howard.
You also have a sign and trade possibility with Paul (if I'm not mistaken?) if nothing goes right this year and he doesn't sign an extension with Celtics. It would be our version of Cleveland situation when they lost LeBron. We could at least get something for him so it isn't like we are giving Rondo away for a one year rental. However, I would argue the risk of a one year rental of Paul is worth the possible reward of an extension and the possibility of him being the piece to put us over the top in attracting Howard.
You never know, they might just win a ring this year with Paul.....I would trade Rondo for another title hands down.