I'm almost postive that's what the SF unit sitting down in our rail yard is....
Here's what they look like...
http://www.angelfire.com/fl3/railrunner/CF7/cf7.htm
Apparently they were fairly common with several roads owning them.Athearn has a RTR model of them,very peculiar looking.
Only ATSF rebuilt F-units into CF7s. After the rebuilds between 1970 and 1978, all were sold off between 1984 and 1987. With their fairly short second lives, most were snapped up by shortlines.
My own opinions, but first an explanation. This is how I tend to group locomotives:
Early
All FMs and Baldwins. EMDs through GP20 and SD24 (they have the same design style as the GP7/9 and SD7/9, which are definitely first-gen). Alcos through end of RS and RSD series. All cab (non-cowl) units.
2nd Generation
All U-boats and Dash 7s. EMDs from GP30 to end of Dash 2 line. Centuries and MLW M-series.
Modern
EMDs from GP/SD50 onward. GEs - Dash 8 and up.
My favorites from these eras, then:
Early - Baldwin Centipede, centercab transfer, Sharknoses. FM C-Liners.
2nd generation - DDA40X, SD45, SDP45. C630, C636, M636.
Modern - Easy; the SD80/90MAC.
I don't consider all of these good-looking. There's no such thing as a good-looking Baldwin, but they're interestingly ugly.