https://deitymic.com/products/pr-2/https://proav.co.uk/audio/deity-pr-2-pocket-audio-recorderThis is not out yet, but if it is as good as it sounds like (-132dBV self-noise @ +30dB, 32-bit float, PiP of 3V / 5V / LINE Switchable, 30h on 2 AA batteries, very small), this is going to be the ultimate recorder for stealth taping. The only thing I don't like is that it seems to be 48 kHz only (I prefer to record at 44 kHz), but I'd be more than willing to overlook this for the other features.
In my experience, my CA-11 cards are around 16 dB quieter than the internal microphones of the Zoom H1 and the Roland R-05. They've never ever overloaded either of those recorders with a battery box, and if I decide to use my CA preamp, I can safely use a +15dB setting on the preamp if I set either of those recorders to unity gain (Zoom H1 at level 16, Roland R-05 using Line-in at level 40). Between the pre-amp and the recorders, I find that I usually use between +25dB gain (for loud shows) and +15db gain (for extremely loud shows).
So up to +30dB gain with such low self-noise (and 5V PiP to boot! might even be able to skip the battery box), with 32-float recording, sounds absolutely perfect.