Here's a little trick I ran across a couple weeks ago. I have a client that needed more dimensions on certain accounts. They'd been using the first two User Defined Fields (UDF) in the account card but needed more, and needed to be able to pull this data into SmartList. Unfortunately, the canned SmartLists expose only the first two UDFs. So, here's how we resolved the issue.
* click image to enlarge
First, you need to use SmartList Builder to use this solution. That's because UDF #3 and #4 for some strange reason are not exposed in the canned SmartLists even though they are stored in the same table as UDF #1 and #2 - GL00100. Go figure.
Next, replicate the appropriate canned SmartList using SmartList Builder and expose UDF #3 and #4 in your new SmartList. (UDF #3 and #4 are identified in GL00100 as USRDEFS1 and USRDEFS2).
Finally, change the UDF labels in the General Ledger Setup window (Financial>>Setup>>General Ledger) and enter the appropriate field values for all UDF's in your account cards.
Now you can run your SmartList and sort and filter on all four UDFs instead of just two.