Fingers crossed it'll cut ally

[birchy]

If it were me, I'd be looking at suction cups of some sort. Maybe some of these: 2 Acupuncture Massage Suction Cup Heat back Pain Relief | eBay but it might be difficult to remove the work piece once it was under vacuum.

The other option might be to use dent pullers like these: Mini Dent Puller Bodywork Panel Remover Removal Tool Car Van Suction Cup Glass | eBay but attach them to the machine and activate them with an air cylinder or some other mechanical actuator.

On the syringe theme, you could use air cylinders to create a vacuum. You could either use one air cylinder and actuate it manually or use 2+ with one as the actuator (i.e. you feed one with compressed air and it then pulls the other(s) to create a vacuum). Air cylinders are not cheap to buy new but can be manufactured at home if you have a decent lathe. Hydraulic cylinders are another option (minus the oil!). Or the scrap yard...

[Ross77]

Might have the wrong end of the stick as I haven't read all posts from the beginning but if you are looking for a vacuum pumps then most compressors can used the other way around, especially the diaphragm pumps.

Clarke Mini Air Compressor - Wiz - Machine Mart Bit pricey but easy to mod, just fix a tube to the intake filter plate and keep the output open. depending on the amount of vacuum you need you could use the smaller 12v tyre inflates or even a fish tank aerator.