As far as signature loans, that really just means any unsecured loan/line of credit, and those are still done. Is this loan for a start-up or an existing business? If the business has been in existence more than 3 years then getting a loan shouldn't be a problem as long as your credit is good. If it is a new business I would try to get in contact with an SBA specialist at whatever bank you want to use. They will have the programs you want to use as a start-up. The big national banks usually have more lenient credit standards than smaller/local banks, and whoever you go with, you will probably have to guarantee the loan yourself.
Also, what type of business is it (llc, corp, sole prop? and do you have a tin?)