It's not keanu getting paid too much money, it's the movie execs not wanting to dish out the money. You really think that the company that produced The Matrix is so poor right now? Hah, I dunno how big of a company did the Matrix, but even if it is a small one, the money that they made on The Matrix is probably more than enough to pay Jet Li his asking price.
I dunno, I don't really think Jet Li would fit right, however, it depends on whether he'd be a good guy or a bad guy and the script.
BTW, these movies are supposed to come out when? 2001/2002?