I am just finalizing my W5500 design and have squeezed it into the same footprint as the WIZ820io which I have been using in another design. So this new module can drop in without changes into this older design and also multipurposes some of the pins to simplify interfacing in newer designs.
There was also room to incorporate a small Cortex M0 + 16Mbit Serial Flash on-board as which means when I port my very compact code over then it can not only run as a serial server but also web and ftp as well, so it’s stand-alone too!. I’ve brought out Rxd and Txd onto the 10 pins in compatible format as well. The idea is that the M0 would always allow access to the host system even if the host software is in control normally. The reset is also bidirectional so it can reset or hold the host in reset if necessary, perfect for remote debugging or serial ISP.
Since WIZnet only had chunky W5500 modules I was forced to do it my way and make a few improvements along the way too Although this is primarily for internal use I may consider selling them as well.
[color=#FF0000]edit: Just changed the name to W5500IoT to reflect it’s usage in the Internet of Things.[/color]