In the way of small preamps, there are (including historical and current models) the Aerco, the Beyer MV100, Sonosax sxm2, EAA/Aeta PSP2, Aeta PSP3, Sound Devices MP2 and MixPre, and the Naiant littlebox.
I'm sure this list isn't all of them, just some I can think of off the top of my head. I don't think any are smaller than the Aerco MP2 though. Beyond that, they're all probably pretty much in the same ballpark for size.
The tinybox does not do 48v phantom, and can't be configured to since the blocking capacitors needed to block the 48v DC are too large to fit in the tinybox case. I'd imagine this would be the case for any 48v preamp attempting to be that small, so I'd doubt there are any 48v preamps the size of the tinybox out there.
Not to re-open your mic question, but the smallest solutions are probably to use the tinybox with schoeps caps and schoeps CMR cables (and no bodies), or similarly to use the Beyer ck930 caps and cables with a custom made tinybox (again with no bodies). There are some threads with pictures on these options.
Short of that, getting a pair of mics that can run on 12v phantom like the Milab vm44-link and pairing them with a tinybox also yields a pretty small solution.
I'm curious if there are any 48v phantom preamps out there smaller than the Aerco for use with any 48v mics (thus not including the schoeps nbox solution). I can't recall any options though smaller than than those on the list above.