Is there such thing as like a “SmartDuplicate”?
Example; you duplicate a part, move it 5 studs up, then u duplicate it again, roblox automatically moves it 5 studs up again because it knows thats what you did last time.
I could really use this, is this such a thing?
I haven’t heard of anything like this, unfortunately.
Can you or someone else post it as a feature request?
(I do not have access)
It is not allowed to post on someone’s behalf, unfortunately. However, you can still request a feature on Roblox’s support page.
One way of doing this is to use separators and duplicate objects using Archimedes. Just set the angle to 0 if you want to duplicate in a straight manner. After that, you can just delete the separators, and it’s all good. :]
You could just make your snap to grid how many studs you want to move a part.
This may be possible using the command bar, but I don’t know how to use it. 
This solution is not really automatic but it’s near that
Firstly go to the Model panel at the top, the one near Home. Second, check move if you hadn’t, then adjust the number to 5 since that’s what you want. Lastly, duplicate your meshes by using ctrl + d, why not pasting (ctrl + v), pasting it will end the object on top or below, unlike duplicate, it’ll end up the same position as the copied mesh. After duplicating you can move it anywhere you want.
To summarize the topic:
1.) Go to Model and change the move option to 5 since that’s what you want. 
2.) Duplicate your mesh or object by using ctrl + d.
3.) Move the mesh
Also a tip, press ctrl + l to make it local movement, that helped me so yeah
model:SetPrimaryPartCFrame(model.PrimaryPart.CFrame + Vector3.new(your,axis,sizes)
The only issue is, every model would have to have a primary part
for normal parts
part.CFrame = part.CFrame + Vector3.new(your,axis,sizes)
Unless i am misunderstanding you could also achieve this by doing
local model = game.Workspace.Example--where your part is located
for i = 1,10 do
local CModel = model:Clone()
CModel.Parent = workspace
CModel:PivotTo(game.Workspace.Example.PivotPoint * CFrame.new(0,i,0))
end