There has never been a SOO LINE GP7 diesel loco sold in O scale.
The Soo Line GP7s and GP9s were repainted into the bold SOO scheme rather quickly after the 1962 merger.
Re: the Soo Geeps - I'd be on board for a maroon/gold version, but not the newer white/red. Have enough of those engines already. The following indicates it took about 8 years to get all the Soo Geeps repainted after the '62 merger - not very quick. Some information from another source:
Soo's first GP-7s were delivered in the diesel switcher scheme (black with yellow stripes). The GP-9s were delivered in the maroon and gold road engine scheme, which it appears was introduced with the Soo's F units c.1949-50.
The Soo's red and white with black lettering scheme was introduced in 1962 IIRC. Most early GPs were repainted into that scheme by about 1970. BTW the GP-9s lasted a long time, running on, among other places, the old Minneapolis Northfield and Southern line in the eighties (often with an orange and black ex-Milwaukee MP-15); at least some of them lasted long enough to be repainted into Canadian Pacific red in the nineties.
It appears that all maroon and gold Soo engines had been repainted into red and white by about 1970. A few Soo engines that were in the "switcher" black and yellow (like the AS-16s) stayed in that scheme til retired in the seventies.
Soo didn't really didn't push to chop the noses of it's early GPs. SOO GP-9s thru the 1980's-90's and seemed to be high nose engines. None were still in maroon, they were red and white and later a few got the all-red scheme. Some high-nose GP-9s were repainted into the CP's version of the all-red scheme.