If you just want to try Phazerville firmware on Teensy 4, all you need is a normal (not VOR) version of the Ornament and Crime boards... with Teensy 3.2 installed in a socket. (sadly, it seems many were built with Teensy 3.2 hard soldered). If the PCB has a pogo pin that touches the reset pad on Teensy 3.2, cover it with tape so it doesn't touch the bottom side of Teensy 4.0. Then just unplug the Teensy 3.2 and plug in a Teensy 4.0 and program it with the Phazerville firmware. However, other than getting all the apps / applets in a single firmware image, there's not a lot of reason to use Teensy 4.0 on those old PCBs if you already have hardware with Teensy 3.2.
But if you're asking about beta testing the new PCB design I've been working on recently, which is optimized for Teensy 4.1, at this moment you'll have to wait. The first PCB rev has a few minor but important issues, so I haven't sent PCBs to anyone yet, not even to DJ Phazer. Sadly, I lost momentum on it a couple weeks ago when the old forum server hardware crashed. While I got the forum back up with new software on a new server in only a couple days (restored from a daily SQL dump backup), many minor issues with the new forum (and dealing with the onslaught of spammers) have taken quite a bit of my attention for these last couple weeks.
Much work remains on the software side before this new hardware can become usable. If you look at my Phazerville fork, you can see I started working on auto-detection of the PCB and edits to Phazerville's drivers for encoders and trigger edge detection. Not visiable on github at this time is a lot of earlier work for test code to use FlexIO for the 16 bit ADC chip and 8:1 mux, and similar code to initialize the new DAC chip. I hope to get back to Ornament and Crime stuff by the weekend, to ideally get the rest of the PCB tested well enough that I can confidently order another set of PCBs.
So a best case scenario is looking like another PCB rev in a couple weeks (but a worst case could be much slower). If I'm happy with the next PCB, the very first will go to DJ Phazer since he's actively maintaining the firmware. He'll probably publish YouTube video demos, so follow his channel to get notifications. When you see those demo videos, that'll be the time to ask about joining beta testing.
OLED on SPI1 and the 8 channel DAC8568 chip are working well (but the rest of Phazerville still know of only the first 4 channels). The ADC33131 chip is also mostly working by FlexIO, just a few minor issues to clean up.
Yes, a 2nd PCB rev was made. It's on my desk now. Unless any major problems turn up, next week I'm planning to send hardware to the authors of Phazerville and Squares & Circles. I might also send one to "mxmxmx" (the original Ornament and Crime creator) if he says he'd like early hardware. So far he hasn't replied, and my guess is he'll probably prefer to get the final version. And after building and testing this board, even if no problems turn up I probably will make a 3rd PCB rev just to add test points that make hardware troubleshooting easier.
You can also see on the Phazerville github commit log, that pull request was eventually merged and another commit went in just days ago to fix a bug (my fault). Not earth shattering news, but progress definitely is being made.
In a classic example of everything takes longer than anticipated, after I got those 2 units soldered I didn't really have a plan for how I would test them. While the Phazerville firmware now has low-level drivers for the new hardware (most of it anyway) none of the rest of the code supports it yet. After a couple false starts, I ended up hacking many lines of test code into a copy of Phazerville to print (to the Arduino Serial Monitor) all the raw ADC and other inputs, MIDI inputs, and a few commands I could send by from the serial monitor to override all DAC outputs and send a test MIDI message. I'm not a musician with a modular synth setup, so I ended up soldering several little adaptors from patch cords to my multimeter, a monitor speaker, and other stuff. It's a good thing I put this work into testing, as both of the PCB sets I hand soldered has a few places I missed.
Today those 2 hand soldered units are shipping to DJ Phazer (Phazerville firmare) and EH2K (Squares and Circles firmware).