Ok, I am aware I am bumping an old thread, but I have some good reasons:
For once I know Sednaiur is NOT gone as I "feared" and thus I would like to make a few suggestions for the pack.
A desert variant is not available here. The best tileset I found fitting is this one here:
https://www.mfgg.net/?act=resdb¶m=02&c=1&id=36175
It is different from the Rocky variant which is more like a mountain theme.
Also as an extra background for generic desert levels:
https://mfgg.net/index.php?act=resdb&pa ... 1&id=36174
So, if you want to make your own set ... ok but in case people are seeking for a really great SMB1 desert tile set I think this is THE ONE.
BTW: I find recreating the old backgrounds from SMB1 difficult in the sense that I can only make assumptions about the settings of the parallaxing backgrounds (so it is not about the image editing stuff). If you look at 1-1, for example, I think the green hills have something like 0.5, the clouds 0.25. All the backgrounds in caves or castles could have 1.0 or maybe even 0.75.
SMB1 on SNES also "only" has a width of 16 tiles on the X axis (compared the first screen of a SMB1 playthrough with the map of Vg chartz), where as in SMBX it is 25 tiles.

I don't know if there is some kind of "camera zoom script" or something similar, because I don't even know how the screen display works in the game and according to which rules.