Hi Hortie,
Other mattresses that also use about 6" of 100% natural or organic Dunlop latex (with either a single 6" layer or two 3" layers) that also use a wool quilted cotton cover would be “fairly similar” if the firmness of the latex was the same and the covers were also “functionally similar” (such as the type and amount of wool, the quilting pattern, and the thickness and weave or knit of the cotton cover).
If you let me know your city or zip code I’d be happy to let you know about any of the better options or possibilities I’m aware of in your area. The mattress shopping tutorial also includes a link to a list of the retail or manufacturer members here that sell mattresses online (in the optional online step) and many of these make latex mattresses that use different types and blends of latex with a range of features, options, price ranges, and return/exchange policies and and a number of these that also have 6" of latex would be somewhat similar as well.
As far as I know they are still making the Pure Echo mattresses. You can see their page with the descriptions of their different options here.
Assuming you mean the Ikea Morgongava latex mattress … it uses high quality materials (85% natural latex made by Mountaintop Foam) and also has a wool quilted cotton cover so it would certainly be well worth considering as well. There are also some comments about it in this topic and this topic and this topic and a forum search on Morgongava (you can just click the link) will bring up more comments ad feedback about it as well.
Phoenix