The maker of OSTTOPST says it supports Outlook 2007. But, yeah, converters for 2007 are scarce.
http://osttopst.net
"Our software successfully and performs OST to PST conversion with recovery of .OST file data from the corrupt, damaged, inaccessible offline storage files. It supports ost recovery and ost to pst conversion from the user mailboxes created with MS Exchange Server 5.0, 5.5, 2000, 2003 and 2007. The converted and recovered mailbox items are then saved to a new .PST, .EML and MSG files. The new created PST file preserves the original folder structure of the bad .ost file, making it easy for the administrator or user to work with."
Recovery Toolbox for Outlook doesn't seem to support 2007, unless they just haven't updated their web site.