Email contact through zxdesign.info doesn't seem to have worked so I will try here.
We'd like to add an eight channel ctc to the zx spectrum next using ports 0x183B through 0x1F3B. There are no conflicts currently according to the page as it is today and I've spoken to Jan (mb03) about it already. I think he's the only other developer actively creating new hardware at the moment.
So I'll go ahead with this unless I hear otherwise.