Hi BillT83,
It really depends on how you define 100% natural and whether you are talking about 100% of the ingredients in the final product or whether 100% of the latex that is used in the final product is natural (NR) vs synthetic (SBR) or a blend of both.
There are certainly latex cores (both Dunlop and Talalay) that use 100% natural rubber with no synthetic rubber in their formulation and by “convention” these are usually referred to as 100% natural latex meaning that all the rubber that is used to make the foam is natural.
On the other hand … any foamed rubber core includes other chemicals or substances that are necessary to manufacture the foam (such as foaming agents, curing agents, accelerators, gelling agents, antidegradants, sometimes fillers, and others) so the final percentage of rubber in a 100% natural rubber core (outside of any fillers it may include) are generally in the range of about 90% - 95% or occasionally a little higher.
In other words … there is 100% natural latex … and there isn’t … depending on how you look at it 
I certainly agree with your comments about Mark.
The innersprings they use are from Star Springs which are very high quality coils and are made by the same manufacturer that is used by Carpe Diem and Duxiana both of which have mattresses that sell for thousands more and in the case of Hastens in multiple 5 figures (although of course the springs are not the only reason for their prices). They are very high quality coils and they use them in spite of their higher cost because they are so well made and perform very well in the mattress designs they use.
The biggest part of the “value” of a mattress purchase is its “functional value” which means how suitable a mattress is for someone in terms of PPP and higher performance components can be a significant part of this. There is more about the most important parts of the “value” of a mattress purchase in post #13 here.
Having said that, I also think highly of ScottJordan and they are a member of this site but differences of opinion are more of the norm in the industry than the exception and I certainly don’t agree that a Talalay latex support core is unsuitable for higher weights in the right firmness level and in the right design for those who prefer it over an innerspring. There are certainly people who would strongly prefer an innerspring support core over a latex support core and the same is true the other way around and I would treat this as a preference choice.
This would also be the “norm” for most of the better specialty retailers who don’t have sales very often at all and when they do they they are often subsidized by the manufacturer and for smaller discounts. The “norm” is that they sell their mattresses for the best price they can every day of the year and don’t tend to negotiate or give preferential treatment to consumers who are better negotiators. In many cases … a retailer who will “negotiate” their prices is more of a warning sign than anything else because it means that they are selling their mattresses for more than they need to in most cases.
Radium Talalay is roughly comparable to it’s Latex International equivalent in most cases although the shipping costs for the other components may certainly be part of the price. In general though I would consider the Berkeley Ergonomics mattresses to be much better value than most of the mainstream alternatives.
You’re certainly off to a good start … and thanks for the feedback
Phoenix