Here is my idea for a new CD32 expansion which is small enough to fit inside the CD32 and have the expansion bay cover placed back on and screwed in (maybe not pushed all the way on, but enough to cover the hole).
I have named it the Redback, after one of Australia's deadliest spiders, known for hiding up behind things out of sight and biting you in the backside, which I thought was fitting for a small expansion which hides up the back of a CD32 and packs quite a bite itself.
The Subway USB plugs directly into the female Clockport and floats inside the bay area the same way it does from an A604, an IDE-CF adapter with a CF card would be attached via a ribbon, as would any Clockport expansions connected to the regular Clockport. For Clockport expansions that are designed to press directly onto the A1200 motherboard (they don't use a ribbon) a small adapter with two male headers plugged into a ribbon should do, or use a 4-port Clockport expander on a ribbon.
There is plenty of room for all these expansions to hang and float around inside the CD32's expansion bay area since the Redback itself won't fill any of that space.
This way your CD32 gets 8MB FastRAM, IDE storage (which can be broken out to a Master and Slave device if you want to feed a ribbon out, perhaps to a faster CD/DVD drive), and expansion possibilities for USB, 16bit Audio + MP3, High-Speed Serial and Parallel, Battery-backed Clock, and possibly more expansions in future, like a Funnelweb Wireless Clockport Card.
There should be a header that a switch can be connected to, so the expansion can be completely disabled for when you want to play The Chaos Engine or some other game which refuses to work with expansions. The switch could be attached inside the plastic expansion bay cover, hidden away at the back.
I don't know anything about the circuitry involved but I wanted to share this idea with anyone who could potentially design the PCB and build them. I noticed Kipper show some interest once, and Jens has the tooling to produce the CD32 expansion connector and may be willing to help if we go through official channels.
I think this expansion would be very appealing to any CD32 owner, even those who already have a SX-1 or SX32, since it offers further expansion options with the Clockports, and since the design is so simple compared to older ideas it should be cheaper to produce and purchase.
So which looks better, the red PCB and black connector, or black PCB and red connector? Personally I prefer a red connector on a black PCB since it resembles the animal its named after more, and it just looks a bit different.