If you have the 2008 compression available (Enterprise or Developer editions), you should be able to trim down your big database using compressed indexes and tables. The MS whitepaper "Data Compression: Strategy, Capacity Planning and Best Practices" should be able to help you find what you need. Quote from it:
"The data compression feature in the Microsoft® SQL Server® 2008 database software can help reduce the size of the database as well as improve the performance of I/O intensive workloads. However, extra CPU resources are required on the database server to compress and decompress the data, while data is exchanged with the application. Therefore, it is important to understand the workload characteristics when deciding which tables to compress. This white paper provides guidance on the following:
How to decide which tables and indexes to compress
How to estimate the resources required to compress a table
How to reclaim space released by data compression
The performance impacts of data compression on typical workloads"
Here is a shorter explanation.
You can find an estimation of how much space you can save by using the stored procedure sp_estimate_data_compression_savings.