I have searched many of the usual sources and can't seem to locate
replacement lamps; as a last resort I could go to Pacific Parts but they
are
so expensive. These are just inexpensively made tiny bulbs with wire
leads.

Any suggestions?
========
Suggest you have a look at QST -Sep 2003 , page 38 .
There you find an article : Solid-State Those Pilot Lamps , by AD5X

Since your bulbs have wire leads you can readily replace them by a LED (of
your desired coulour) and an appropriate resistor.
After that you can forget about replacement for ever .

Good Luck

Frank GM0CSZ / KN6WH