well i have bin figuring on it for a while now,
think this http://hellgate.ingame.de/skilltree/engineer/?l=50&s=128430230020322002006450000 would be a quite good enginner that shuld have a tanking robot that are wearing wart´s leg, i dont have those requires in my head but it will be enought.

the things he is going to handle is : tanking in a 3 player game ( me, a bm, a evoker), but still be able to kill both in party and alone.

im nott sure if i shuld go with more in armor retrofit, medpak retrofit, shild generator retrofit to get better tanking and team play.

1think this can be the best build but im nott sure, plz comment with what you think or KNOW about it.

Here's the one I'm using for my engineer, and I'll link the post that talked about it as well...

http://hellgate.ingame.de/skilltree/engineer/?l=50&s=123130210321a020710000a0000

Basically, the main differences between yours and this one are that the one I linked are these... The reduced bits:
Less points in Rapid Fire (doesn't matter as much for the value as MM)
Less points in Construct Drone (either it lives or it doesn't... giving it more health is less useful than more armour)
Less points in Beacon (First point is 25% boost, after is only 5% each, making it less useful)
Less points in Sword Retrofit (You can assign it willpower if you need to, easier than you can add in more points)
NO points in Tactical Mode or Advanced Tactical Mode (Locks you up too much, can't use it enough)
NO points in Bomber Bots (Already have 2 bots)

And the boosted bits:
Max Master Engineer (Insane armour on drone makes it a great tank)
Max Molotov Assault (Igniting enemies is more useful than phasing them)
1 point into Escape (Always good for emergencies)
3 points into Concussive Crash (As a prerequisite)
Max Haste Bot (31% increased RoF and Skills for the whole group is Uber)

Here's the guy's posting explaining the main reasonings he has.

http://forums.hellgatelondon.com/showthread.php?t=73003

really good idea maymne, but is the robot really surviving good when it´s a 3 player party ? or more.., and yea that build really makes insane dmg.

Since you have over 1500 armour on it, and can heal half its health every 11.4 seconds... Shouldn't really be too much of a problem, in general. Remeber also, that's 11.4 seconds for healing, without counting haste bots... those cut off almost a third of the time.

ah it´s so hasting bots work, really good xD