I agree that the best option is to find Star dies, second best is to turn down standard dies, and as a last resort drill and tap the head for standard dies. It really isn't as simple as just drilling a tapping the head for standard dies. In the very least, you will have to turn down the bottom of the sizing die so it will fit into the the recess of the shell plate. Otherwise you won't get full length sizing. You will probably also need to modify the powder slide housing to get clearance for the seating die, and modify the seating die to get to clear the tool head spring and screw.
I used to own a Beldon Tool head which came standard taped for 7/8-14 dies. I had it set up for 9mm, but it took a lot of work. I had to drill and tap the expander hole to use an RCBS expander plug. I used Lee dies for the rest of the stations, and they had to be modified as above.
Attached is a picture of the Berdon Head on a Star Reloader set up for 9mm.