the HDCombo addon for the PSTwo Slim serves nearly the same physical functionality as a chubby PS2 with network adapter.
I was fed up of always having to disattach the HDD from the HDCombo to put it into my PC or an external USB enclosure.
So that was the time where ubergeek and me had the idea of modding the fix-soldered IDE cable of the HDCombo to fit to a standard 3-Point UDMA133 IDE cable, so that both the HDCombo and an external USB enclosure can be connected simultanously to the HDD,
which would've made ANY cable/HDD switching gratuitous.
I bought some raw IDE 40-pin cable (3 meters), some connectors and a tool to crimp those connectors into the cable.
After building a male<->male IDE adapter with it I tried to connect both hosts (PC and HDCombo) while always having turned off the power of one of them (e.g. HDCombo powered down, USB enclosure device powered on, both connected via IDE), which didn't work.
But the whole setup works when only the HDD and one host adapter are connected, like HDD+HDCombo (via IDE male<->male adapter and UDMA133 cable), or HDD+USBEnclosure.
The big difference from a standard HDCombo setup now is that I only have to plug the IDE cable into the adapter I need (like USB for game transfer and HDCombo for playing).
NO HDD SWITCHING NEEDED ANYMORE.
Note that this is just a proof-of-concept, but this method should also work for chubby+network adapter users!
Pictures of the mod