Is there such a device category?
Server machines (rack, SAS drives..) can offer 8 RAM slots, usually sporting 32-64GB RAM, and are common enough to be cheap to purchase... but not to operate (100s of Watts)
Low-power solutions (used laptop - mobile processor, low-power RAM, etc) typically offer no more than 8GB (16 being the largest I've seen), but can operate @ 30W, a value I am guessing a desktop computer can't approach (I could be wrong).
A Google search for low-power servers floods me with offers of ARM computers with integrated RAM, always too little.
Storage is not a problem, and processor can be any 2+ core (even ARM). It's just the RAM that matters - lots of it, on a single computer. What should I look among?
[edit] Not looking for bleeding edge tech, more economy.