Oh wow, interesting project... I've also been working on a "better c" for a few years, and while it was originally a JIT language (using jitasm), I recently switch to MIR, but since I already had my own lexer/parser/etc stack, I ended up changing it to basically lower everything into a node_t compatible AST tree and handing that off directly to c2mir, bypassing its parser.
Maybe you're interested in collaborating? :)