Engineer is widely used by many companies (illegal or not). Technically it might be wrong if your working at a consulting firm but its not working at an OEM. I think you will find even non-PEs in some consulting firms are still using engineer for their juniors. Fact is, these rookie engineers are probably not interacting with the customer much and even if they were and they have a PE signing for them, nobody is going to care one way or the other.
This subject has been beaten, battered, and buried. There are many threads dicussing using the term engineer in ones title. I think the consensus is, yes some places it is illegal, but no one ever says anything about it (except BobPE and a few others - where are you Bob?) and many companies do use the word engineer for their non-PEs (almost all OEM's give their engineeers the title of 'engineer' even if no PE). Also, I honestly dont think this is illegal. Laws are written, regarding engineering, thinking of only the consulting world and I honestly doubt they meant to include OEMs. If they did, to bad because everyone does it and rightfully so (except in the consulting world).
You have to come up with your own title? What titles has your company used in the past?