By default Ubuntu 11.10 with unity interface has a 2x2 workspace, however I am used to have a single row horizontal 4x1 workspace with 4 desktops. I haven’t found any option under settings to change this, but here’s a workaround:

Edit the file ~/.gconf/apps/compiz-1/general/screen0/options/%gconf.xml and add two new gconf entries as follows:

\<?xml version="1.0"?\> \<gconf\> \<entry name="hsize" mtime="1317329603" type="int" value="4"/\> \<entry name="vsize" mtime="1317329604" type="int" value="1"/\> \</gconf\>

Edit the hsize and vsize values to fit your needs :)