OK, I've been loooking for 5 strings.

Ebay has alot of tenors that can be had pretty cheap.

You might find a tenor or mando-banjo with a decent pot that you could add a vega style tone ring to pretty cheap.

The pot I have is a mando-banjo with a bad neck I picked up for about $45.

Something like that would be cheaper than building a whole new pot.

BHSC