Regarding the change of the limit of one2many fields please refer to question https://accounts.openerp.com/forum/Help-1/question/6627/

Regarding the filter I had the same requirement for one of our modules and I have solved it with the following steps. Assume that you have the following one2many field which you want to filter:

'line_ids': fields.one2many('your.model', 'script_id', 'Lines'),

1. Add a filter field to your model:

   'ir_filter_id': fields.many2one('ir.filters', 'Additional Filter', domain=[('model_id', '=', 'your.model')]),
   

2. Add a one2many function field to your model:

   def _get_lines(self, cr, uid, ids, fields, args, context=None):
       line_obj = self.pool.get('your.model')
       res = {}
       for script in self.browse(cr, uid, ids):
           args = [('script_id', '=', script.id)]
           if script.ir_filter_id:
               args += eval(script.ir_filter_id.domain)
           line_ids = line_obj.search(cr, uid, args)
           res[script.id] = line_ids
       return res
   
   def _set_lines(self, cr, uid, id, name, value, inv_arg, context):
       line_obj = self.pool.get('your.model')
       for line in value:
           if line[0] == 1: # one2many Update
               line_id = line[1]
               line_obj.write(cr, uid, [line_id], line[2])
       return True
   
   'view_line_ids': fields.function(_get_lines, fnct_inv=_set_lines, string='Lines', relation="your.model", method=True, type="one2many"),
   

3. Add the two fields to your form view

So you can filter your one2many field with any domain. You only have to be aware of the following points:

- The filter is stored in the DB and all users have the same filter - You have to save the form view so that the current filter becomes active