What are the most likely sources of possible tachyons?  We would likely need a source so that we can use them in an experiment in an effort to prove their existence.  Once we have them we can devise an apparatus to manipulate them into causing an effect that won't be explainable by any other means.  To do that though, we not only need a source but also we will need to know their properties, specifically, their speed... how many times the speed of light is it?  and is it a constant speed?  We need to know this so that we can create the apparatus to manipulate them.  It should be pretty simple.  It could be based on a version of early atom smashers (so that we can keep the cost of creating it cheap)... maybe a simple linear accelerator?  It would have to be redesigned to work at the faster than light speeds.  The problem here is I think the tachyons may have to be charged for them to work in the machine though.