@Admin I've got the same chip as the axon! and I've got a 2560 sitting pretty just waiting to go on my next board
... That is if I don't decide to upgrade to an xmega or avr32 board. Side note, the avr32 chips look awesome the high end ones have up to 210 MIPS and have DSP functions like interfacing with cmos cameras.
What I've been looking into is trying to create a static library using the avr-ar part of the GNU toolchain. That way, the linker will only add in functions used. I'm just not sure how I use the avr-ar (archiver aka librarian) command line utility. I don't have alot of experience with command line stuff.
Its more of an OCD tendency of mine to want to make everything I code as small as possible. I've got 7K of Sram and 40K Flash to spare. I'm not even close to filling the chip.