I did a startup with 3 people on full time. I don't like the inflated title either, but it's necessary for raising funds or selling a company. People want to know who's taking responsibility. Some use light-hearted titles like "Dictator" or "Astro Girl" but I find those less appropriate. If my job is to convince some guy in a suit to put $150k in my bank account, deal with legal repercussions, audits, and so on, I think it's the appropriate title.

Founder seems to be the other good one, but it says much less about your scope of responsibilities. Founder can be tech or sales related too. I just try to make it clear what the size of the company is.