Using d3dfunc's isometric camera commands means you can use standard 3d to get the look you want.
Here is a very basic example using boxes but it should give you the rough idea.
Rem Make 3 Dummy houses
make object box 1,3,2,3
make object box 2,3,2,3
make object box 3,4,2,3
position object 1,3,1,1
position object 2,-4,1,3
position object 3,-10,1,3
Rem Make Grass
make object plain 100,500,500
pitch object up 100,90
color object 100,rgb(0,128,0)
Rem initialise d3dfunc
d3d_init
rem Set isometric camera
set camera range .1,1000
d3d_set_ortho_projection 0,50
rem this is this camera position that gives the nintendo look and feel
position camera 0,20,-50
point camera 0,0,0
do
loop
Hope that helps. Of course going the true 2d route using Ianm's dll is good too.
Code requires v3.6+ of the dll of course.