The serious part is: I have a little doubt on the viability of RIPEMD160, by the curse of "birthday paradox", approaching 2^80 computation doesn't seem to be too remote. It's just not economical (profitable). At present, the whole network can do 2^66 hashes per second, it takes 2^14 seconds - less than 1/4 day, to reach 2^80 computation. And remember, that is 2 times SHA256 on a block. ASIC's that are computing one-time random SHA256 should cost less and do more.
finding a hash collision for RIPEMD160 is impossible because the chances of it are astronomically small and it doesn't do you any good because you need to have a private key that produces a public key that is then hashed with SHA256 and then hashed with RIPEMD160 that produces the same hash! that is the combination of 3 impossible things!
2^80 is huge and what miners are doing with their 2^whatever hashes per second is not a hash collision find!