So, I used to play with keepInventory a lot, as a sort of middle ground between creative mode and normal survival. Nowadays I've been trying out gravestone style mods instead, in search of more challenge. There's a bit of an oversight/quirk in most of these mods: they don't help you if you fall into the void.
I was hoping somebody would make either an add-on to one of the many grave mods (Tomb Many Graves 2, Gravestone Mod - Graves, Corail's Tombstone, etc.), or create a stand alone mod that tweaks how the void works. If it's an add-on, it could simply make the graves spawn on a block of dirt one or two blocks above the void - but a standalone mod would need to try a bit harder. Perhaps bedrock could be added to all dimensions, and void damage could be made to start 3-8 blocks above bedrock? This way, even if you die by void, you'll still be within build limit.
Anyway, if anybody makes this let me know. As it stands I'm way too paranoid to play sky-block or venture to the end.