Dear Jon,
> Does anyone know if the Pali text for the Mahavamsa Tika is online
> anywhere?
You can find this .tiikaa on tipitaka.org. For some reason the title
there is spelt Milida.tiikaa. It is included under Anya:
Sihala-gantha-sa"ngaho. The text matches the Milinda.tiikaa, ed. by
P.S. Jaini. It is appended to the Milindapa~nho, ed. by V. Trenckner
and published by PTS. The .tiikaa takes up 73 pages in the PTS edition
which is rather small considering the size of the Mahaava.msa.
Best wishes
Jim