video interface cables like to break-- so really, the best screen is the one that you get lucky enough to not have break on you..
for shipping, not really sure what carputing companies are in australia, and not really sure if there is anywhere in la that you can just purchase a car vga touch screen-- though i am in central america, and no one around here stocks anything carputer related, so i have to order most of my carputer specific stuff online...
power usage. old laptops, and netbooks(eee pc) are a popular option for carputers
the power supply issues seems to be less of a issue than what you might think--in the last year that i have been posting, i would estimate that i have seen maybe 50 dc-dc noise topics-- out of hundreds of carputers, and most of them are related to teh m2 power supply, which would not work with a laptop install-- the search feature can tell you more info on that, or check the "ADV. FAQ" at the top of the screen for even more general carputer info.
radio stations use the same tuning bands (odd thenth numbers-- ie: 97.1, 97.3, 97.5, 97.7, 97.9, 98.1, etc.) so should work fine.
you get around this by using whatever you have available-- either a bunch of rca y-adapters, or using external crossovers, or by daisy chaining your amp inputs, and using the amps crossovers. there is no single "cut-and-dried" method to this, just as long as all the amps get the correct signal..
and just in case, you missed the easily hidden adv faq link: