I am not sure about which modern are all brass, but I know that vintage rocks. Classic Gillettes, Gems, and Schicks are all I own. Get your friends hooked on the classics.
I recommend taking the zamak bashing with a grain of salt. Compared to brass and ss it may be inferior but that does not mean it's as evil as some make it out to be. There are many stories of people having one zamak razor for over a decade without issues. I think the hobby side of shaving has taken it's toll on zamak. People babying their razors by taking them apart after every shave instead of every blade change accelerating the wear on the threads significantly. This is a treatment that some stainless steel razors seem to favour otherwise the blade could stain the razor.
Even though I favour plated brass, this does not make me fear zamak.
That's a good (and simple) observation. Multiply the disassembly by 3-4, and the threads take 3-4 times the abuse, and your razor could break 3-4 times quicker (emphasis on "could")... Ironically, due to the fact that you continuously "maintained" it.
The Micro Touch One pitched by Rick Harrison of Pawnstars claims to be chrome plated solid brass as does the new VDH. They seem to be a rebranded 9306 Weishi razor which makes the same claim. Not all Weishi razor models are solid brass.
This thread has pretty much already listed the materials used in various models of modern razors, but for any who might like to see a complete list of materials and manufacturing techniques used, check out the Buyer's Guide for Currently-Manufactured DE (Safety) Razors in our wiki: