To my understanding of metal properties, once you stress metal ( ie smashing the front end ) you loose alot of the metals strength then cutting and welding the chassis with a vertical join I dont see how it will be stronger.
Being a qualified panel beater just means you can do the job on the sly , My dad and brother are both qualified panel beaters and they both said its illegal straight away .
You would have been better getting another car where the chassis is okay (maybe a roll over ) then build from there.