I got the BDC working with Access 2007. Here is the LobSystemInstance I used to get this working:
<LobSystemInstance Name="MyInstanceName" DefaultDisplayName="MyDisplayName">
<LocalizedDisplayNames>
<LocalizedDisplayName LCID="1033">English Display Name</LocalizedDisplayName>
</LocalizedDisplayNames>
<Properties>
<Property Name="AuthenticationMode" Type="System.String">RevertToSelf</Property>
<Property Name="DatabaseAccessProvider" Type="System.String">Odbc</Property>
<Property Name="RdbConnection Data Source" Type="System.String">Data Source='';Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=\\server\share\database.accdb;Trusted_Connection=true;</Property>
<Property Name="RdbConnection Integrated Security" Type="System.String">False</Property>
</Properties>
</LobSystemInstance>
I hope this helps!