Alex I agree, it takes a lot of time to configure, but we have made some nice-looking professional communities with UNA. You need to be prepared to pay for a PRO licence and some additional modules, but it's possbile to do. See http://itshub.in.ua as an example.
its more a community than a professional driven community but thanks for sharing. i am talking of a website like linkedin somehow but not as complex of course. with the job board module and professional profile fields plug in, those are the two things that really are missing as of today.