Scott,
the Predicta seems to be one of the most plentiful vintage sets out there, at least if you go by what eBay has to offer every week.
They have been collectible for a very long time and therefore I would guess there are plenty of survivors, many of them still work or can be made to work.
I think the rarest are the Continental ( a Danish Modern variant of the pedestal) and the Penthouse which has a seperate CRT housing connected by a long flat cable.
I have a "Holiday" model myself, mostly because it seemed a TV collector just should have a Predicta.
it's not particularly my favorite set though.
I have heard rumors that Philco dumped a lot of unsold stock into the ocean back around 1962
They had a lot of CRT problems and some have said they drove Philco into bankruptcy.
Eric