Amazingly we are asked this all the time. Being new to this we asked the guys at Kickstarter.
Here is their guidance:-
"Pledging to a project on Kickstarter is about showing your support for a creative idea, and less like buying things from a store. That's why backers can only pledge to each project once. Accordingly, it's not possible to select multiple rewards or tiers."
However please feel free to ask through the 'contact me' button at the top of this page and we can ensure that we can create a package of rewards that suit you personally.