Hi lax2luv,
Welcome to the Mattress Forum! 
The Pure Echo (as you may have already found) is quite a good value for a quality non-foam mattress. Regarding firmness, you’ll tend to find most non-foam mattresses to be on the firm side, especially as the fibers compress over time and some people do add wool toppers to achieve a bit more plushness without the aid of foams. Post #3 here has some of the better sources for these I’m aware of.
I do get asked this question once in a while, here is a very incomplete list with some examples of some manufacturers that make mattresses similar to what you are looking for (innerspring/natural fibers with no foam) to give you some ideas and a sense of the wide variety of designs and pricing available. Some of these include latex which you may want to exclude but you can look on their sites to see what they have available.
https://www.vivetique.com/ see here as well daxstores.com
Lifekind® Certified Organic and Naturally Safer® Since 1997 and their sister company www.omimattress.com/
https://royalpedic.com/default.asp
www.sleeptek.ca/ see here thenaturalsleepstore.com/products/sueno-...spring-mattress.html for an example
landandsky.com/index.asp see here for examples thenaturalbedstore.com/organic-mattress.asp
ADMIN NOTE:Removed 404 page link | Archived Footprint 1: daxstores.com |Archived Footprint 2: thenaturalsleepstore.com/products/sueno-...spring-mattress.html |Archived Footprint 3: landandsky.com/index.as | Archived Footprint 4: thenaturalbedstore.com/organic-mattress.asp
Phoenix