you can buy the bow templates already cut out for you. one place is rhinestonetemplates.com. You can even ask for a custom template in a particular pattern if you want. then like you mentioned, you can buy rhinestones in bulk at many places including the site I just mentioned. The stones are very easy to brush in, you just buy a paint trim brush, lay your template on a cookie sheet, pour some stones on it, and gently sweep them in the holes. You will also need transfer tape to lift the stones out of the template and lay on your bow. Then, you just iron right on top of the transfer tape.
Although its not really endorsed to use a home iron to press the hotfix stones on, they can be done with a regular ole iron turned up to the highest heat, no steam. you just have to be careful and test how much time you will need on some small samples first since your iron doesn't give you a temperature and they are all different. Don't be fooled into thinking you can't do this on a minimal budget. Buying a template is around 20-25 bucks average so it is possible to add this look to your home bow business
Granted a heat press saves a lot of time but once you start offering the rhinestone bows, you can easily save enough money just from one big order to buy a press.