Has anyone heard the Sumiko

I realy doubt that Sumiko phono box will be able to reproduce cartridges with lower than 2mV output voltage.
You'll probably need to get Monolithic sound that has settings up to 53dB of gain. With Monolithic sound you can run cartridges down to .6mV + there are impedance adjustments.

Marakanetz, have you heard the Monolithic phono stage with a low output MC? Does it work good, or is it just another Black Cube or Phonomena wannabe?

...yes, buddy.
Phonomena and Black cube are able to drive lower outs than Monolithic, but presicion and detailability of Monolithic is unbeatable at its price offered(almost twice less than 2 of above!).
I've tried recently Monlithic in my current setup with .9mV cartridge but with passive preamp and I figure out that 53dB gain is good enough for my setup.
Having some sencitive preamp >200mV on input and with moderate gain of 10dB will give you a possibility to drive >.4mV cartridges.
The math is very simple: to get the output phono stage voltage just use cartridgeVoltage * 10^(dBgain/20) and match with input voltage of preamp. ^ is used for the power.
Monolithic outboard power supply is available and it's much bettern than Black Cube or Phonomena battery offered.

Marakanetz, I recently purchased a demo Monolithic PS-1 for $300 and I can't belive how much "presicion and detailability" I'm getting. It's hooked on one end to my 'new' Melos SHA-3 hybrid preamp and on the other end to my infamous modified Technics 1200 w/Ortofon X5 MC(2 mV). I do not have the outboard PS but the unit it's plugged to a Tice A/V Solo conditioner. Bass is stunningly visceral, highs are detailed yet extremely musical. Soundstage is very good, too! The analog rig humiliates my Cambridge D300SE/Soundtream DAC-1 combo.

You and I are pretty much along the same lines. Just that you bought the wrong turntable...

This will be of no service to you whatsoever, but I have just bought a Sumiko phono box as a stop-gap until something better comes along (like an A-R PH3-SE) but I use a m.m. since I'm a lo-fi kind of guy, and running it into my AR LS8 Mk 2, it sounds fine to me. So like I said, I am giving you an absolutely decent answer, unfortunately it's to the wrong question.