Hi!
I've been looking at the atmega1284 chip the past few weeks, and I think it's a great chip if you need a LOT of flash memory, and more IO ports. The only problem is that the AVR it selves costs about 17$ with shipping from ebay. that's about the price of a Mega2560 (clone).
Since I don't need that much flash memory, I started looking for other, cheaper alternatives. the difference between 1284 and 644 when it comes to price isn't big. just a few dollars (at ebay). still, the smaller Atmega32A costs about 4$, and also have a lot of IO pins.
does it exist an Arduino bootloader for the Atmega32A? is there a cheaper place to buy AVRs than ebay?
I've bought an Atmega32A from Farnell in the UK. It cost me about £4. I have it on a breadboard and bootloaded it with an Arduino Uno. It works fine apart from digitalRead not working for some reason.
These links should help you get going with the bootloader.
eBay is weird for electronics parts. There are some bargains. And there are some sellers that look like they're buying at full list price and selling at double that, just to rip off the people who think that they can't buy from regular distributors...