Workbench mill, corona corn mill derivative
Something that bolts on a table, can be fitted with stone or metal mill heads, is powered by hand or bike or motor or wind or donkey...
Size: about the size of a sheet of A4 paper
Corona grain mill (need open source photos) derivatives are very common in America, comonly sold for as little as $20 on craigslist, ebay... but cost $50 for shipping to Europe (4.5kg weight). They were patented by US patent in 1909 (apparently) or 1925  and design is believed in the public domain (where is the patent?). Many are older models made by companies in Colombia (ie Corona, is Landers the same company?) (), others are sold new on ie. Amazon, and are made in China.
Grain vs pulse: Steel head = only coarse matter-corn, beans etc are ground, stone head = flour!
The two hard parts to develop are the stone or metal head, and the drill auger.
Wondermill sell a 'stone burr' or 'metal burr' set for 45-55$ []. Also available in Europe for 35-40 EUR. The cheapest option is to use 2 paving slabs, cut with an angle grinder in circular/polygon shape. Not sure about safety of grain ground with this artificial stone though, best to use natural stone?
We have the drill auger fron a wondermill and from a genuine Corona mill, they seem somewhat similar.
Wondermill also sell practically every part that could be incorporated into (a) (specific) design of desktop mill, US and EU shops.
A rectangular sheet steel base plate has a steel pipe welded at 90 degrees, this pipes length is 'to suit' the mill user. On top of this pipe a
Development: (4-5cm?) steel pipe is welded at slight downhill angle, the mill auger sits, and is held, in this pipe, so on top a hole has been cut and a pipe has been welded to enable grain to feed in, with a big plastic bottle cut as corn hopper. On the power end of pipe, a handle is welded at 90 degrees to enable turning of the auger by hand, pulley or a die shape to enable motorised turning will be here. On the mill end you want a hollow disk welded on the outside of the pipe to enable attachment of whatever burr you choose.
Modifications to Corona mills:
Motor-isation: many videos on youtube etc
Maya mill, pedal powered Corona mill: Bicycle Mill/Corn Thesher 
- Power Cube - Power
See Product Ecologies for more information.
This hammer mill is worth replicating by Factor e Farm: