The R-Tank changes probably won't happen, as those are sprites, and would thus require two sets of sprites. I've created a revised font only; something like that is too minor to change the roles.
Even so, I've tried my hand at making an M-Tank Mega Man tileset:
It's a rather simple edit of the M-Tank from Mega Man 5. I'm not satisfied with how the horizontally stetched can looks, but it's all I had to work with.
While I'm at it, I thought I'd take a look at Mega Man's Sakugarne sprites:
The top row is the original tileset, the middle row shows the tiles assembled into how they look as the finished sprites before being layered, and the bottom row shows the whole sprites.
I've made a slight improvement on the tiles:
What I mainly did is get rid of the black outline around Mega Man's face. It was a holdover from the original Game Boy sprites, which only had a monochrome palette. Since the sprites were converted into colorful NES sprites, the outline was unnecessary, so the edit was done for the sake of consistency with Mega Man's original NES sprites. I also fixed an error on the Sakurgarne layer, which had one of Mega Man's feet still in the second frame.
And finally, another suggestion for the configuration menu:
Since some games have the option to enable or disable music and sound effects, I think Minus Infinity would have it as well. Useful if you want to replace the music in gameplay videos without having to lose the sound effects.