60's pickup truck kit availability

There certainly not too many:

http://www.modelexpress.net/cgi-bin/modelexpress/shop/AMT_6310si.html?id=XFWnvrcG

http://www.modelexpress.net/cgi-bin/modelexpress/shop/REV_7613.html

http://www.modelexpress.net/cgi-bin/modelexpress/shop/AMT_38207.html

http://www.modelexpress.net/cgi-bin/modelexpress/shop/AMT_Y925oc.html

And don't forget that some cars had pretty good towing capabilities:

http://www.modelexpress.net/cgi-bin/modelexpress/shop/AMT_38530.html

http://www.modelexpress.net/cgi-bin/modelexpress/shop/REV_7648.html

I don't think any of these are currently being made but you can usually find them on ebay or on a dusty shelf in the occasional hobby shop.

AMT / Ertl 1957 Chevrolet Cameo, you can use the stepside bed from the 55 kit if you want that style bed.

AMT / Ertl 1960 Chevrolet Fleetside

Revell 1964 / 1965 Chevrolet, fleetside and stepside available

AMT / Ertl 1967 GMC stepside

AMT / Ertl 1972 Chevrolet or GMC fleetside.

There has been a '60 Ford kit but it is not easy to find and usually comes with a high price.

Resin adds some options

1958 Dodge sweptside or stepside  http://seltd.net/

1957-60 Ford http://resinrealm.net/

1957 Ford http://www.modelhaus.com/index.php?c=4138&p=69573

1958-66 Chevrolet http://www.modelhaus.com/index.php?c=4064