Updated to version 1.2. The status bar was converted to Asar and also compatible with SA-1 hacks now. The code has been optimized and only hijacks needed parts instead of copying the whole routines over and over and thus saving a little space. The status bar can be modified like any other and should still work fine on the bottom.
Updated to version 1.1. Layer 3 images won't be affected anymore since the status bar will be on top, if there's a layer 3 image in the level. A small glitch with Magikoopa (CGADSUB settings) has been fixed as well.
The patch has a few issues that need to be addressed before it can be accepted. Layer 3 levels and mode 7 boss levels will crash if there is an item in the item box. Fortunately this is a relatively simple fix, and is caused by an error where "LDA #$0F" is "LDA #$0F7", forcing 16-bit A and messing up the code after.
The other issue is that mainscreen-subscreen settings have been changed, and this results in various graphical bugs in-game. Examples of this are the Magikoopa having no transparency on LoROM, as well as wooden spikes going behind layer 2. On SA-1 these issues are not present, but instead the presence of a Magikoopa causes the status bar to become translucent, with weird windowing effects. On both LoROM and SA-1, Palace switch blocks appear behind the Palace switch messages.
Finally, on SA-1, taking damage from an enemy while an item is in the item box will cause the sprite (or a glitched graphic) to teleport to where the item should fall, for 1 frame before the powerup actually drops down.
Once these issues are sorted, it should be good to go.