A necro mac for vxed would be seriously difficult to code. For one, if you're kiting in there, you probably don't have the HP to take hits from those mobs...so you have to have all of the pathing / casting times down *really* well.
Not to mention, you'd have to do it in a completely different part of the zone from the bard. Only good place for a necro to kite in vxed is the entrance, so you'd also have to check for summoners popping in that middle area...and get pathing files for pulling...and write the code so that if you got a summoner up, you'd either get a new instance (bad idea for a reason I'll say soon) or you'd have to move around it. And therein lies the crux of the problem...the macro would have to be capable of splitting mobs...which would be a tricky piece of code. If, to prevent this, you split the mobs manually in the beginning, you would have a work around...until you got a summoner, and have to drop the instance to avoid it...and end up in the same boat.
Long story short, you're probably better off looking into FH for necros, or just doing tasks.