I have found no 3/8"x24 thread multi-band antennas in my own searches.
Lakeview Antennas does have several single band units that could be mounted on quick-disconnects for band changing. Download their catalog in PDF format.http://www.hamstick.com/catalog.html
Hustler antennas has one choice, also single band:http://www.new-tronics.com/main/html/mobile_uhf___vhf.html
Another possibility is to use a multi-band antenna that has a PL-259 connector. Use this adaptor from MFJ to go from 3/8"x24 to an SO-239 (it appears on page 70 of their printed catalog):http://www.mfjenterprises.com/Product.php?productid=MFJ-7701http://www.mfjenterprises.com/Catalog.php