Send a message to Rick. He's pretty quick to respond. I just had one built and got it a few weeks ago. It took about 8 weeks after order to receipt. I would have had it a little sooner, but I asked him to delay shipping it because I was traveling.
I did eventually reach Rick, nice guy and helpful, mentioned they are building heads and cabs. Reach out to him, seemed busy as others have suggested here.
I started with Scumback H55/H75 but there was too much low end. That combo works very well in my Mills cabs though.
Now I have Scumback M75 on top of J75. I like it a lot, but I miss a little bit of the brightness/tighter low end that the H's brought. I really like the MTL with the BE cab and my Splawn with Creamback H75/V30. - so I am going to try a M75/v30 mix and a J75/v30 mix and see how it does.
I hate being all the way in Australia with crazy shipping prices and massive import taxes standing between me and an MCII. I think last time I checked it was going to be over 7k AUD to have one at my door, and that's just for a head!