There's nothing about lawyers that requires geographic proximity. If you really dislike Chicago based lawyers, hire a lawyer out of a VC-specific lawfirm from SV or NYC.
However, one of the great benefits of Valley representation is the intros you can get to investors. Those investors tend to be local. Thus, the best situation is to be wherever your lawyers and the investors you wish to be introduced to are. (My Chicago-based counsel intro'd me to a few Chicago-based VC firms and no angels or seed groups. There are precious few of all three here.)