Granting your facts, for purposes of discussion ... Sued by whom, pray tell?  The defense lawyer is not an agent of the government, and her/his actions do not (and by definition cannot) violate anyone constitutional rights. Procuring perjury, of course, is a crime (as well as an ethical violation), and the lawyer as well as the witnesses could be prosecuted.  Most defense attorneys are highly ethical and dedicated to law and justice.  That's just a couple of the reasons why your imaginary scenario occurs so rarely, I'm sure.  

"How many criminal defense lawyers ever get disbarred for this kind of stuff?"

  To prevail, though, the client would have to show  things which would likely be difficult. First, in a malpractice case proximate causation must be shown. That means that the client would have to show that the negligently or intentionally introduced  false testimony substantially contributed to the injurious result (verdict or sentence). In very rare instances it might be possible to make the case  that a client was convicted because his lawyer presented such incredible false testimony that it turned the trier of fact against the client and the verdict did not rest on prosecution evidence sufficient to sustain the verdict. As the defense does not present its case until the prosecution has presented its case in chief and survived a motion for judgment of acquittal the frequency of that working would be extremely low. It would seem  that in the vast majority of cases the argument that the jury would have convicted in the absence of the false testimony and thus no causation exists would be nearly impossible to rebut.

  The same general pinciple would apply in a claim to set aside or vacate a judgment in a habeas action. the prejudice prong of the Strickland test would be very difficult to satisfy.

  Also, you might frequently have  "clean hands" issues. I'd go out on a limb and state that the large majority of false testimony in defense cases comes out of the mouth of defendants and the argument that I lost my case because my lawyer told me to/allowed me to lie isn't likely to be viewed with favor. In cases where other witnesses provide false testimony, it likely would be the case that the defendant had a hand in procuring it in a large number of cases as well. That presents estoppel, contributor/comparative fault/ assumption of risk, etc. issues.

  Therefore, most of the actions against defense lawyers accused of suborning perjury, etc. are going to be disciplinary proceedings or crimnal cases because the only party with standing to sue the lawyer for such misconduct (the client) probably won't have a very good case very often, but it is possible for it to occur.