The big catch with those cheapie units you guys are posting links to
is their low screen resolution. Only ~270 or ~240 lines of pixels? :-
P
(they also have small battery capacities from what I can tell)

Since none of these "roll your own" systems are going to be IGC-legal
for badges/records, why not simply use an IGC-legal external computer/
logger with its own GPS (a la the ewMicroRecorder or similar)?

Ditching the GPS component from the PDA/PNA means a simpler device
with a much lower power consumption level. Seems to me that there are
a lot of non-graphical (but IGC-legal) loggers and flight computers
out there, and most work fine. Its the moving-map/navigation aspect
that needs work - so why not concentrate on that?

And If your GPS fails, you _do_ have charts in your plane... don't
you??

--Noel