Actually, that's exactly where my initial quest started (I've had a discussion in Russian here that led to my fruitful collaboration with hyperborean on that adapter).
Such adapter will work on any InterWave-based card, but it will require hardware modifications made to the host card (the only one that can be used without any soldering is the GUS PnP Pro thanks to its JP8 header that contains all the needed signals in the most useful form).
So, generally speaking, you'll have to do the following in order for the adapter to work on a generic InterWave-based card equipped with at least one SIMM30 slot:
1. Check if your card already has any embedded memory (your Compaq card should have 512KiB in a SOJ). Identify what bank(s) it will be assigned to (0-3).
2. Install any working SIMM30 in the slot and identify what bank it will be assigned to (0-3).
3. Remove the embedded memory chip (I guess, disconnecting its power lines should be enough, but I may be wrong).
4. Install the SIMM72 adapter into the slot.
5. Connect the three wires (CAS1-3) from the adapter to any combination of the following pins of the main InterWave chip (remember, that one BKSEL is already assigned to the SIMM30 slot, thus you shall not connect any wires to the corresponding pin of the InterWave chip; also you may connect 2 CAS wires to the relevant SOJ soldering spots as it should be easier - that's why you had to identify the way your GUS incarnation interprets its slots and chips):
Pin 94 - BKSEL0,
Pin 95 - BKSEL1,
Pin 97 - BKSEL2,
Pin 98 - BKSEL3.
6. If everything has been connected correctly, enjoy your 16Mb GUS PnP clone card!
DISCLAIMER: DO AT YOUR OWN RISK
The pin assignment given above has been taken from *PRELIMINARY* AMD InterWave datasheets (attached):
AMD Am78C200 InterWave LC - the chip used in Expertcolor MED3201 board,
AMD Am78C201A InterWave - the chip used in Compaq Ultra-Sound 32 board (the latest revision of the InterWave),
AMD Am78C201 InterWave - the chip used in all boards except the two mentioned above. This datasheet also includes data on a non-PnP edition of the InterWave named Am78C202, which I have never seen in any production boards.
According to these datasheets the pin assignment is the same as far as the BKSEL0-3 signals are concerned (except the smaller Am78C202 edition).
I haven't actually checked if all other pins are the same, but they are, it could give us some ground for a possible upgrade for original Gravis boards (replacing original Am78C201KC chips with the more advanced AM78C201AKC revision, but if you ask me what the differences are - I have no idea).