How can I use a custom table as a node type?
While you're making work for yourself using a custom table and not the Field API, you can use your own table with


hook_node_load ( load data from custom table into node )
hook_node_insert ( insert record in custom table )
hook_node_update ( update record in custom table )
hook_node_delete ( delete record from custom table )


You'll probably also need


hook_form_alter


if you want to add form elements to the node form.

Keep in mind the Field API will do that all for you though if using standard fields.