Used monitor under$600 with good bass low levels

The Triangle Titus ES has twin input connector sets and can be biwired or biamped. (I have a pair.) So can the Comète ES I imagine.

Tobias,

You're right, Triangle Titus can be biwired. I had forgotten. Same with Titus 202s I own. Probably also the case with Comete.

It would make much more sense to design from scratch just buy the drivers that Bolzano use and copy the dimensions as closely as possible (drivers are usually around $50 each) - DIY clones are common enough (more common for classics though). Nevertheless the whole thing will take skill and you will probably need to experiment to get the right sound. I'd build something simpler to start with though.

I can't imagine what you will do - in my minds eye I see two used monitors strung together with hockey sticks, duct tape and bungee cords?

Shadorne,
Close, you forgot skiis. They come with release bindings in case the doctors show up I can quickly dismount the craziness.
I plan on consulting with Meniscus, they have been in the business for a long time. I will let them help choose the drivers and design the cross-over and other parts.