With the amazing indexing algorithms available today I would suggest a general search field which shows results as follows .....
Search is : "xyz"
Results are :
There are
10 invoices that contain xyz
There are
6 estimates that contain xyz
There are
3 bills that contain xyz
There are
9 items that contain xyz
There are
4 Contacts that contain xyz
or.......
Search is : 99.95
Results are :
There are
10 invoices that contain 99.95
There are
6 estimates that contain 99.95
There are
3 bills that contain 99.95
There are
9 items that contain 99.95
Clicking on the links (ie estimate) would produce ....
estimate 12345 contains xyz
estimate 12346
contains xyz
estimate 12347
contains xyz
estimate 12348
contains xyz
estimate 12349
contains xyz
estimate 12350
contains xyz
Which are links to the documents !