And their small competitors?
Let's hear it for the little guy, who faces unfair competition from multi-nationals paying no tax anywhere. There is an argument for ensuring these companies pay tax, since government is unfortunately a necessary evil and has to be paid for.
One can look at their global profits (a number they have reasons for declaring and maximising) and tax them on a percentage thereof, the percentage of global sales in your country. Seems to me a treaty along such lines would give each government a fair share and the multinational pays taxes like everyone else. The actual rate - and permissible write offs for R & D etc. - on its home share would be a matter for each government, while the company can of course simply stop business in a state which sets a stupid rate.