You can create a custom Login Page by modfying "modules/Users/login.tpl"
Custom Modules can be created through Modulebuilder or manually.
When creating modules manually it's important to use the right names.
The easiest way is a Plural name for the folder, table and Module and a singular name for the class.
Manual steps:
You need a Folder in modules/ named like you module (i.e. CAccounts)
In this folder you need a file named like the class (i.e CAccount.php) with something like that as content:
require_once('data/SugarBean.php');
require_once('include/utils.php');
class CAccount extends SugarBean{
var $table_name = 'caccounts';
var $object_name = 'CAccount';
var $module_dir = 'CAccounts';
var $new_schema = true;
var $name;
var $created_by;
var $id;
var $deleted;
var $date_entered;
var $date_modified;
var $modified_user_id;
var $modified_by_name;
function CAccount (){
parent::SugarBean();
}
function get_summary_text(){
return $this->name;
}
function bean_implements($interface)
{
switch($interface)
{
case 'ACL':return true;
}
return false;
}
}
In this folder you need a vardefs.php file:
$dictionary['CAccount'] = array(
'table'=>'caccounts',
'audited'=>false,
'fields'=>array (
//Your fielddefs here
)
);
require_once('include/SugarObjects/VardefManager.php');
VardefManager::createVardef('CAccounts','CAccount', array('basic'));
For the language and metadata folders look at any other module.
Next is a file at "custom/Extension/application/Ext/Include/CAccounts.include.php"
$moduleList[] = 'CAccounts';
$beanList['CAccounts'] = 'CAccount';
$beanFiles['CAccount'] = 'modules/CAccounts/CAccount.php';
A language file for the module name must be in "custom/Extension/application/Ext/Language/"
$app_list_strings['moduleList']['CAccounts'] = 'Custom Accounts';
To display the Module in your tabs you need to use "rebuild and repair" and then the "Display Modules and Subpanels" option in the admin menu.
For a custom module you don't need the "custom/" folder structure. Files there will be used by sugar if provided, but often there's no need for that in a custom module.
Guides about the Module Framework can be found on the sugarcrm support site:
http://support.sugarcrm.com/02_Documentation/04_Sugar_Developer/Sugar_Developer_Guide_6.5/03_Module_Framework