By vote of two-thirds of the qualified electors thereof voting thereon, any county, city or incorporated town or village in this state may become indebted for and may purchase, construct, extend or improve plants to be leased or otherwise disposed of pursuant to law to private persons or corporations for manufacturing, warehousing and industrial development purposes, including the real estate, buildings, fixtures and machinery; and the indebtedness incurred hereunder shall not be subject to the provisions of sections 26(a), 26(b), 26(c), 26(d) and 26(e) of Article VI of this Constitution; but any indebtedness incurred hereunder for this purpose shall not exceed ten percent of the value of taxable tangible property in the county, city, or incorporated town or village as shown by the last completed assessment for state and county purposes.