You could also use some sort of USB enabled device - like arduino or some FTDI USB chip
as you want. I did such a device with an atxmega controller for a machine which gives some simple IO
that i use with labview application for displaying some process values. I did this via
a virtual serial port (called CDC) which is very easy to use an requires no USB
related programming.
Then you can connect to VISA serial functions an communicate strings.
With very little labview code you should the be able to decode and count the edges
of the button input.
With this solution you should also be able to do more complex USB IO in future.