Hi needanewmattress,
These types of questions will depend on the specifics of a mattress and all the materials and components inside it interact together and can only be answered based on your own personal experience on the mattress “as a whole”. Assuming that by “progressive support” you mean “compression modulus” or the rate that a material or component becomes firmer with deeper compression … the compression modulus of a foam is the “rough” equivalent to the spring rate of an innerspring but even this can be misleading because a spring has a linear response curve (at least if it has the shape of a cylinder and has a single spring rate) and foam has a response curve that is shaped more like a banana. There is more technical information about this in post #2 here. A single spec of only one component of a mattress will have little to do with whether a mattress “as a whole” will be a good match for you in terms of PPP. 2 lb polyfoam would generally have a compression modulus in the range of 2 or a little higher but it would depend on the specifics of how the foam was manufactured and the compression modulus of deeper layers may not be nearly as important as the compression modulus of the upper layers in a mattress (because deeper layers don’t compress as much so their firmness can be more important than their compression modulus or spring rate).
Yes there are many manufacturers that still make them although they are much more rare in the more mainstream part of the industry. There is more about the pros and cons of two sided mattresses in post #3 here and the posts it links to. A few examples of two sided mattresses that are made by some of the members of this site are here and here and here and here and here and here and there are many other manufacturers that make them across the country.
I don’t recommend specific mattress brands (outside of smaller manufacturers or “off brands” in general … or at least the ones that make good quality/value mattresses) because outside of PPP … a mattress is only as good as it’s construction and the type and quality of the materials inside it regardless of the name of the manufacturer (see post #5 here and post #10 here). I also don’t keep a record of individual mattresses that are made in any particular area or by specific manufacturers since this would be more than anyone could keep up with in a constantly changing market.
Outside of the list which Benstark linked (thanks Benstark :)) … post #21 here also has some links to local lists that are close to you but your better options would likely be in the NY, NJ, or CT lists.
Phoenix