I'm a huge fan of the SoapyLove line. I've seen her Soap Pops and they're probably a good 8 ounce size.
I don't know where she gets her molds, but here's a site that has a nice round up of popsicle molds:
http://www.thekitchn.com/thekitchn/swee ... lds-053409It should give you a good lead (looks like Amazon.com is a good place to start judging from the Google search I just did). It'll be fun to see how you change up the basic soap pop and make it your own with a unique design or two =)
I hope this helps.