CRM is specifically not designed to be distributed across multiple SQL environments for a number of reasons (most of which are business rules oriented); however there are things that can help AND there are numerous large corporations running CRM in internationally disperse offices.
WAAS do make a difference when it comes to Latency issues.
Also you might want to read all the new white papers from Microsoft on performance. There are a number of them.
If you have not upgraded to v4.0 that is a big one and if you can SQL 2008 has a number of key features that are all performance oriented.
This blog post might help
http://www.crmlady.com/2009/02/tackling-performance.htmlAnne