We recently bought new foam to replace our over cab bed mattress.
We used Upholstery Decor, Inc in Goleta. The owner, David, is a character (dry wit) and knows his stuff. He took over the business from his Father and has about 50 years experience (he started working in the shop when he was just a kid) he also sells online. He has a website with a foam education video that is worth watching.
http://www.foamonline.com/types.php?cartID=36bd644f4ae8227b4b3600887f31db45
I am a big guy and the old mattress was too soft for us. We sampled some foam and found that Medium Firm was a bit too soft and Extra Firm was too hard. Also we liked the High Resilience foam better than the High Density foam so we went with 4" High Resilience (2.8 - 3 L
foam in a "firm" ILD (around 50).
We have 4 nights on the new mattress. Much more comfortable than the old mattress. I think we may add a good quality 1" softer foam topper but it is satisfactory as is until then (we are presently camping our way to and from the Seattle area along the coast).
For High Resilience foam if you are under 200 - 225 pounds you will probably prefer medium (ILD around 30) to medium firm (ILD around 40). For folks over 225 lbs you will probably like a medium firm (ILD around 40) to Firm (ILD around 50). Best to try before buying.
Our new mattress including the two separate cushions in the slide out portions (we have a Queen size in total) was about $400 plus tax for foam cut to size and stuffed in our existing FWC mattress covers. High density foam would have been about $150 (or more) cheaper but we are happy with our selection and it is worth every penny to be able to sleep comfortably without bottoming out and having uncomfortable pressure points.
BTW: I brought along two ThermaRest 1.5 inch mattresses (from our backpacking) just in case the new mattress was not adequate and we have not needed to use them.
Watching the foam education Youtube video (at the link I pasted in above) was key to communicating with David in order to get the right mattress. However, I strongly recommend trying the various foams before buying - and I mean laying down on it on a hard surface like a floor (if you can find a supplier where you can do that). David insisted that we do that and that was key is deciding on the FIRM ILD 50 over the Medium Firm ILD 40.
David said he can make a custom foam mattress out of different density foams if we need it. He said he could modify the mattress we bought to do that if we needed him to.
I hope this info is useful to other folks.
Craig