Hi Jmoss,
In my previous post I indicated that Zinus was not listed on the Certi-Pur site however I just checked and they now are. This is good news. I will be going back to previous posts and correcting those that indicate they are not listed.
Zinus has a Chinese factory and owns many brands which are often sold through box stores like Costo and through various outlets under many names. These include Spa Sensations, Night Therapy, Vivon, Mattress in a box, Keetsa, and others. They are usually lower density foams however the Spa Sensations is a higher density foam so it would be worth consideration. The density and ILD of the support foam can play a significant role in how the mattress feels and how well it supports the heavier parts of your body to ensure good spinal alignment so I would certainly make sure that this was known as well in any memory foam mattress I was considering. Memory foam is a good pressure relieving material however it is the least resilient of all foams and so has the least ability to support or “hold up” the heavier parts of the body which is one of the two main functions of a mattress. This is why the support layers under the memory foam and the thickness of the memory foam layer itself are so important (it needs to be the correct thickness for an individual’s weight distribution and sleeping positions).
There are certainly higher density memory foam mattresses which meet my criteria that are under $1000 (queen) however they usually involve “wading” through the noise of many memory foam mattresses that IMO are not worth considering.
The link you posted is an airbed (called the Natural form SAT bed) with memory foam in the comfort layer. IMO an airbed is the worst of all possible support layers both in terms of performance and value. There’s much more information about this here.
Sleep EZ Is one of our manufacturing members who sell a high-quality memory foam mattress online which uses 5.5 lb Sensus which is among the highest quality memory foams and is made by Foamex. It is under $900 (queen). Their Select Sleep line of latex mattresses can also be ordered with 5.5 lb Sensus instead of latex in the top layer. Note added later: This mattress was discontinued
http://www.furniturerow.com/ A regional manufacturer with an outlet in Albuquerque. They also carry Simmons mattresses which I would avoid. They have several memory foam mattresses that may be worth looking at. From some initial research into the memory foam on their site, it seems that their suppliers include Flexible Foam (Which are Certi-Pur certified) and Kaymed (an irish foam producer which is well known in Europe). It may be worth asking some questions to see if they can fill in the gaps of the information on their website.
There are some examples of memory foam sources that use certified foams and will give you reliable information about what is in their mattress in the online memory foam list here.
There are many more reputable online outlets who provide memory foam for those that don’t have access to a local manufacturer so I will gradually add to this list as time permits but I wanted to correct the error in the Zinus memory foam before I went to bed 
Phoenix