Hi chavala,
You can see some comments about the Loom & Leaf along with many of the other “simplified choice” online mattresses in post #2 here in the simplified choice mattress topic and the first post in the same topic would probably be worth reading as well. There are also some more detailed comments in post #5 here. A forum search on Loom Leaf (you can just click the link) will also bring up more comments and feedback about it as well.
You can see my comments about a solid surface support system under a mattress in post #10 here. While it’s true that they can add some additional risk because of the lack of ventilation under the mattress … in most cases if there aren’t any additional risk factors they would be fine. As an example I have an adjustable bed with a solid surface under my mattress but I don’t have any other significant risk factors so I don’t have any real concerns about any mold or mildew issues.
Platform beds are more of a furniture item which is somewhat outside the main focus of the forum and aren’t something that I spend a great deal of time researching since there are so many different options available and mattresses take up most of my available time.
Having said that … there are a few options listed towards the end of the foundation reference post here that may be helpful (although you probably won’t be able to test them in person either).
Phoenix