Its possible using related fields. First you need to inherit the sale order model and add a related field for product brand id For example:
from osv import osv, fields
class sale_order_line(osv.osv):
_inherit = 'sale.order.line'
_columns = {
'brand_id': fields.related('product_id','product_brand_id',string='Brand',type='many2one',relation='product.brand')
}
sale_order_line()
Then need to inherit the sale order view. Sale order line tree and form view is specified inside the sale order view. SO inherit the sale order form view using xpath.For example:
<?xml version="1.0" encoding="utf-8"?>
<openerp>
<data>
<record model="ir.ui.view" id="view_order_inherited_brand">
<field name="name">sale.order.brand</field>
<field name="type">form</field>
<field name="model">sale.order</field>
<field name="inherit_id" ref="sale.view_order_form" />
<field name="arch" type="xml">
<xpath expr="//field[@name='order_line']/tree/field[@name='name']" position="after">
<field name='brand_id'/>
</xpath>
</field>
</record>
</data>
</openerp>