Keep in mind that the Black Carapace is what makes a Space Marine a Space Marine. Many of the implants don't function in a lot of Chapters, or don't work properly. For example, the Imperial Fists and their successors don't have the acidic spit glands. The reason Space Marines, including Scouts, are T4 is because of their Black Carapace, though, and without it, they can't interface with their armour at all. Scouts are, in Codex Chapters, fully Space Marines physically, but are untested in proper combat. It's sort of their rookie year, for lack of a better term, to serve in the 10th Company.
If you want elite Troops who aren't Space Marines, but still have decent armour, consider Sisters of Battle or an Imperial Guard army with the Stormtroopers and Grenadiers doctrines (as that combination lets you have five Stormtrooper squads.)