Re: Replacing windows and need to match siding
If all you change is the height of the window, then you could easily trim and fill in underneath it with new siding, basically, extend your side window trim legs to the ground, then run lap siding in between the trim legs.
If you change your width, you could still do the same thing, just salvage the siding under the window to fill in along the sides, then run the trim down and side in between.
Another option would be to find a custom millwork shop and have what you need made, it's an expensive way to go, but it would preserve the look of the house nicely.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!