Where Do You Get Your Surety Bond From?

In my experience, the actual bid bond is 'shopped' among different underwriters to get the best terms. 

I believe insurance brokers have access to the minutiae and enlisting an independent insurance broker is the path I'm most familiar with.  Many major banks and insurance companies offer surety bonds.

Bond premiums can be a big bite out of cashflow at a busy time of year, so individual terms that vary according to project sizes/payment terms/ and purchased inventory are big factors in picking the right one, IMO.

I would suggest reaching out to your current business insurance provider to see what they offer.  We developed a relationship with a local independent insurance firm that handles shopping them around to underwriters as Brian stated.  That has been very beneficial for us.