Jamie,

Do you need a hold down (for wind, seismic, lateral loads) - or just a locator?

If just a locator, you might be able to use a piece of rebar or pipe that is epoxied into the floor and then into the post.

If you need a hold down, you'll need to design the connection for the uplift or lateral loads that you are working with - and that could be a simple bolt / pin connection that would be easy to hide, or something more involved like a T or U plate that could be visible.