Using IN with LIMIT in MySql
There are several different ways to approach to problem.  One is simply to group by the bookmarks you care about then obtain a list of tags for each - the substring_index function is being used to limit the number of tags to ten which are in ascending order.  Order and the separation character can be changed to fit your purpose.

select bm.bookmark_id
     , substring_index(group_concat(tag.tag order by tag.tag asc separator ','),',',10) as tag_list
  from v_bookmark_tag_assoc bm
     , tag
 where bm.bookmark_id in (123,456,678,890)
   and tag.tag_id=bm.tag_id
 group by bm.bookmark_id