I’ve recently had to cancel a Knickerbocker The Rock bed frame I had ordered simply because my mattress arrived a lot thicker than I expected it to be and I want to keep my overall mattress height (with bed frame/legs) no more than 26 inches.
I stumbled upon these bed legs called Universal Bedlegs, they are essentially just attach directly to the bottom wood in foundation and act like bed frames to support the mattress set (with foundation).
Link: http://www.universalbedlegs.com/home.html
They are made of tough plastic and have a lifetime warranty, I’m not too worried about the plastic material not being able to hold up simply because with 9 legs to support the foundation frame durability and maximum weight support should be a non issue and probably more dependent on the built quality and durability of the foundation itself rather than the support legs beneath it.
What’s got my interested in these be legs is that they come in various heights most notably the low profile 3" height which caught my attention plus once installed they can be adjusted to any height afterwards simply by getting a different height (just the legs, mounting bracket no needed).