It's pysically impossible to build a VHS deck that would fit into a PC without designing the PC around it...
biggest available slot on the front of a PC would be a 5 1/4" drive bay, offer up a VHS cassette and you'll see the problem :P
insert it sideways? - NO, the tape needs to wrap around the head so needs space to be unlaced from the casette - tends to make the "footprint" of a VHS deck about the same depth as the cassette is wide.
Face it - whatever way you transfer from VHS to digital media will need wires and a VHS player.