Hi eml,
While there are probably dozens of companies that offer blended Talalay latex toppers … some of the best value sources are listed in post #4 here.
Bear in mind too that Dunlop and Talalay are quite different in their performance and feel and that there are many Dunlop toppers that are “listed” as having a softness level that may not be accurate. There is more about this in post #4 and #6 here. If a topper is Talalay … it will usually say so. if it doesn’t specifically say this … it is quite likely Dunlop.
IFD means “Indentation Force Deflection” and for practical purposes means the same as the older term that is still more commonly used which is ILD or “Indentation Load Deflection”. The difference between the two testing protocols (the older ILD and the newer IFD) are very small and have to do with using a 1 lb pre-compression as a base line and a longer delay time between initial compression and the time when the compression force is measured.
Layer thickness and the layers that are both above and below any other layer will also make a big difference in how a topper feels and performs. Local mattress manufacturers (such as Jamestown) and local foam suppliers are other sources that may often sell toppers in various materials including latex. Jamestown’s Talalay toppers are in the lower end of the firmness scale (in the range of 14 - 15 ILD blended Talalay) as far as I know.
Sleep Like a Bear has the widest range of talalay latex available both in terms of material, thickness, and ILD (they carry every type and ILD that is made by Latex International) but as you mentioned they are more expensive than other sources that may not have the same range of choices.
Out of the sources you listed … I would definitely avoid using Foam by Mail (FBM) who IMO are not a reliable supplier. There is more about this in post #2 here along with post #2 here (as well as many other places around the forum).
Hope this helps.
Phoenix