From https://gist.github.com/silasrm/226be07e875d6d03e994

new_gist_file.php

controller:

public function buscaItensAction()
{
	$query = $this->getRequest()->getParam('q');
	$limit = $this->getRequest()->getParam('limit');

	$reg = $this->model->buscaSelect(
		$query,
		$limit,
		array(
			'campo = ?' => $outraCondicao,
		)
	);

	$this->getHelper('json')->sendJson($reg);
}

model:
public function buscaSelect($query, $limite = 8, array $conditions = array())
{
	$_conditions = array(
		'condicao_fixa = ?' => 0,
	);

	$conditions = array_merge($conditions, $_conditions);

	return $this->fetchAll(
		$conditions,
		$limite,
		null,
		null,
		array('id', 'campo1', 'campo2', 'campo3')
	);
}