I want to make a vacuum printing easel for my darkroom. A shallow sealed box made from plastic or aluminium with holes drilled on top and low-profile DC fan mounted at the bottom opening. Small switch will ensure fan is on only when needed. Top surface may require two thin (1-2mm) edges to provide a reference corner for placing paper in complete darkness when printing colour prints. I often use thick insulation tape stuck in L-shape on enlarger baseboard for that purpose. It is easily removable and enough to position a paper in the dark.
I have made some calculations and found out that if corner of paper rises 2mm up from the projection surface the image shifts 1mm towards image center. This applies to any print size provided you print full frame image and use standard projection lens. If this happens during exposure it guarantees blurred image corners. Now I can understand my problems when I was printing without easel.
UPDATE: I have made a prototype from a large plastic tray covered with thick cardboard sealed together with insulation tape. 9cm fan from PC power supply was mounted in an opening in the cardboard and also fixed with insulation tape. I have drilled 30-40 2mm holes under 24x30cm paper size. The tests were pretty promising however I have found that holes should be evenly spread under the whole surface of paper. An isolated line of holes is not able to suck curly efge of Polymax RC paper. However if holes are spread evenly you can see how paper gets flat and stick to an easel surface.
PC type fan turned out to be very low efficient in creating vacuum but I still like the idea because it is small and vibration is not a problem.