[Arran]

You can find much of what you need from Mouser, though getting axial lead capacitors from there is more difficult, you can use radial caps inside the Bakelite block cases, they fit rather well, but axial ones will fit too. I myself gave bough caps from both Radio Daze, and WJOE Radio, WJOE radio is very reasonable if you want bulk film caps, they sell both axial and radial lead ones too, resistor selection is more limited then Mouser of course.
With regard to bulk however there was a series of tubes developed by RCA called "Nuvistors" they used them in TV tuners a lot, and there were also subminiature types, sometimes called "hearing Aid Tubes", the envelopes are the width of a pencil. The main selling point with transistors originally was that they used less power more so then less room, mostly because of not having a filament to heat. Some of the European and British portables show that size really wasn't the aim, they had multiple bands, and big speakers.
Transistors cost more though at the time because they were more expensive to manufacture, and had a high rejection rate, almost 1/2 didn't leave the factory for one reason or another. Some of the early Ratheon ones cost $15 each at retail in the mid 1950s, so needless to say tube portables were around for a few more years after that alongside the transistor sets, and much longer in AC powered devices like TV sets.
Regards
Arran