Fostex has some portable Preamps...you never hear of anyone on TS using them...because of the price I would guess
while true, there are some that you've referenced that largely were only adopted by tapers out of necessity (because the onboard preamps in recorders were bad) and a result of being at the right place and right time in the market for what was being produced, not necessarily by choice. For example, the sx-m2 was almost $1400 brand new, which is about what that fostex clocks in around, but we don't see people using the fostex because for that price now, it doesn't fill a need at a competitive price. That's the advancement of technology (where many onboard preamps have improved). Now the market is looking at mixers and multi-track preamps for that price point (one exception below). I think that largely the function of what we do had fit within an existing market so that market was big enough to create enough demand. Now, that market has moved but our function hasn't and we don't carry enough oomph to generate a ton of products. As a result, boutique shops like Jon or Chris can move in and reap hay.
I was sticking with pres that are commonly used by tapers!!
I think it's largely a skewed snapshot of time due to the aforementioned reasons. Nothing wrong with that necessarily, just something to keep in mind. There are current products, but they may not be made by the same players or fill our needs quite as well as older stuff.
So if you are considering the mixy (which I would argue tapers generally don't use), then I'd add that Sonosax makes a 3ch (2ch post-mixer out) preamp & ADC. (the sx-m32 I think or something like that), and Nagra makes a 2ch preamp (the EMP). All that stuff is top shelf though...