Emacs Org: Display a subset of tasks by context

I wanted to get a quick preview of my top three tasks by context. Since org-tags-view didn’t seem to have a built-in way to limit the
number of displayed items, I used defadvice to add my own. Here’s the relevant code from my Emacs configuration:

(defvar sacha/org-agenda-limit-items nil "Number of items to show in agenda to-do views; nil if unlimited.")
(defadvice org-agenda-finalize-entries (around sacha activate)
  (if sacha/org-agenda-limit-items
      (progn
        (setq list (mapcar 'org-agenda-highlight-todo list))
        (if nosort
          (setq ad-return-value
            (subseq list 0 sacha/org-agenda-limit-items))
          (when org-agenda-before-sorting-filter-function
            (setq list (delq nil (mapcar org-agenda-before-sorting-filter-function list))))
          (setq ad-return-value
                (mapconcat 'identity
                           (subseq
                            (sort list 'org-entries-lessp)
                            0
                            sacha/org-agenda-limit-items)
                           "\n"))))
    ad-do-it))

and the snippet from my org-agenda-custom-commands:

(setq org-agenda-custom-commands
  '(
    ;; ... other commands go here
    ("0" "Block agenda"
         ((tags-todo "+@phone")
          (tags-todo "+@work")
          (tags-todo "+@drawing")
          (tags-todo "+@coding")
          (tags-todo "+@writing")
          (tags-todo "+@computer")
          (tags-todo "+@home"))
         ((org-agenda-sorting-strategy '(priority-up effort-down))
          (sacha/org-agenda-limit-items 3)))
        (")" "Block agenda"
         ((tags-todo "+@phone")
          (tags-todo "+@work")
          (tags-todo "+@drawing")
          (tags-todo "+@coding")
          (tags-todo "+@writing")
          (tags-todo "+@computer")
          (tags-todo "+@home"))
         ((org-agenda-sorting-strategy '(priority-down effort-down))
          (sacha/org-agenda-limit-items nil)))
        ("9" "Unscheduled by context"
         ((tags-todo "+@phone")
          (tags-todo "+@work")
          (tags-todo "+@drawing")
          (tags-todo "+@coding")
          (tags-todo "+@writing")
          (tags-todo "+@computer")
          (tags-todo "+@home"))
         ((org-agenda-skip-function
           (lambda nil
             (org-agenda-skip-entry-if (quote scheduled) (quote deadline)
                                       (quote regexp) "\n]+>")))
          (org-agenda-sorting-strategy '(priority-down effort-down))
          (sacha/org-agenda-limit-items 3)))
    ;; ... more after this
))

This way, I can see all of my common contexts on one screen, and I can decide what I want to work on first.