ISP page could really use some improvement indeed.

It would be nice to list proper SCK/MISO/MOSI pins to use for every official Arduino board as a programmer and as the target, or link to an article that does (which I haven't found to exist).

This is absolutely possible. Enter somethig like this into your boards.txt configuration file.

By easy what I meant was more like being on the menus already.

When I tried to, I managed to burn a bootloader using mega-isp with some pains.

Therefore, I found out that the non-playground page on it could seriously use some improvement.

The page in question is:
http://arduino.cc/en/Tutorial/ArduinoISP

It ignores the auto-reset problem, which is now properly covered in:
http://www.arduino.cc/playground/Code/MegaISP

That page could be linked from the non-playground one.

Setting that aside, it would be nice to list proper SCK/MISO/MOSI pins to use for every official Arduino board as a programmer and as the target, or link to an article that does (which I haven't found to exist).

Besides the documentation issue, Arduino and avrdude could be improved to handle using auto-resetting devices as programmers properly as now suggested in the MegaISP playground page.

Another improvement on the software side would be allowing to use an AVR programmer (like arduinoISP) to upload sketches from the IDE, for easily management of bootloader-less devices.

Just build that as if it was for the duemilanove.

However, you'll need the circuitry (won't be able to use the onboard usb port), as the 8U2 is still acting like an FTDI (usb-uart converter).

It might be doable with the 8U2, but would need to reprogram the 8U2 and make it so that the 328P streams data to it.

Linux can now be loaded. I've ported whatever necessary to make asbestos work:

http://github.com/rvalles/asbestos-avr8susb