I want to build 3 heavy barreled shooting rigs a 6.5-284, a 308 or 300 Winchester and a 338 Lapua.

I have have lot of experience with M70s and M700s and really like the looks of the Nesika Bay/Dakota Tactical action with the picatinny rail milled into it.

These guns will be repeaters, and the 6.5-284 and 300/308 will be built on the Sako 75 pattern McMillan stock with Hart barrels, and be special finishes by Robar. The 338 Lapua will be built on a McMillan A5 stock have the same barrel except length and weight.

What do you think of this action? Any other suggestions?

I want to outsource the barrel to Hart and do the stock work myself. It's not worth $5500 to me to pay someone to do something I can do myself.

Sounds as if you have some very cool ideas for the 3 gun set. I have not built a custom on a sako action but have owned and shot several and all have been very good shooters right out of the box.
The Nesika bay actions are amazing actions, as to the built in rail, I wouldn't care for it on a bolt gun.
My choice would be remmy actions with Krieger barrels with calibers , 223,308 and a powder burner 338-378. I like the 700's due to the fact, there are so many aftermarket parts available.
As to 5500 a pop, I would be looking at the guns built by Darrel Holland, complete about 2500 and they are one holer's if you can do your part.
As to just action and barrel work, there are several top notch smiths on this board that do equal work, Jim Kobe, Mark Stratton just to name a couple.

Take a look at these two places.

http://www.texasbrigadearmory.com/

http://www.surgeonrifles.com/index.htm?id=-1234076074