While Valve has yet to release an update for the Engineer class in Team Fortress 2, a fan has taken it upon himself to do several updates. Unfortunately, I can't access the site for full details, and Kotaku's article is extremely vague, but maybe you can check it out for yourselves. Also, the imbed link button stopped working, so I'm just going to leave some raw urls.

http://kotaku.com/5506096/erectin-a-fan+made-team-fortress-2-engineer-update

http://manno.com.br/Engineer/ (I can't access this site, for some reason; hope you all have better luck)