I'd be surprised if it were easier than LLVM, which is pretty easy.

But if you want to make a language you should absolutely not get hung up on technology. Even though it's very dated, Crenshaw's "Let's Build a Compiler" can teach you everything you need to get started building languages from scratch and by hand, and it moves pretty fast too:

http://compilers.iecc.com/crenshaw/

There are other tutorials out there which will get you places. The first thing to do, really, is make a sketch of the language as you'd like to use it, and get excited about that, and then sit down and implement bits of it at a time. Compiler/interpreter writing is extremely rewarding—you get a lot of payback for your investment. Good luck!

It's actually really easy to take the JIT-compilation engine from LuaJit and use it for the compiler of your own programming language. The LuaJIT code is surprisingly modular, and you can pretty much take what you need.

For scanner/parser generation Lemon and Ragel are terrific. That takes care of building the AST for you. LuaJIT does the heavy lifting and takes care of the architecture specific edge cases. That just leaves the fun part in the middle where you decide on the semantics and syntax of your language.

Yes, totally possible! For example, see MoonScript, a CoffeeScript-like language that compiles to Lua:

http://moonscript.org/

Yeah people are trying to port clojure on LuaJIT.. It is possible.