Homepass has several ways of implementation. If you have a laptop and a wireless router you're well on your way to having a homepass. Homepass does impersonate a Nintendo Zone but does not allow you to connect to it. However, you will be streetpassing everyone else connected to actual Nintendo Zones around the globe as well as others using homepass, and if one of them has the theme, then you will very likely get it. You must have a EUR 3DS though because themes are region locked.
Edit: I should also mention people have gotten homepass working on their cell phones as well, but I have not tried that method.