Before Arduino appeared, embedded hobbyists were more attracted to building their own development boards. If someone needed new feature they simply included in their design. We don’t say that Arduino like approach is bad, but it feels that sometimes it makes us lazy on hardware. There is not much creativity by simply grabbing Arduino, dropping couple libraries out of pool and writing couple lines of compact code. Anyway, if you like to do more barebone developing, Radek suggests his Atmega64 development board which can serve as great prototyping board.
It features many useful functionality like DS3231 RTC, DS1820 1-Wire temperature sensor, 24AA00SN I2C EEPROM, FT232RL for USB connectivity, 16×2 LCD, couple of seven segment LED displays, eight buttons and 16 LEDs. This is great board for learning AVR C programming but also can be used as base platform for many great projects. And if you still want it to be Arduino, then there is no problem to find suitable bootloader for it. Board’s Eagle CAD files are available if you would like to build on for yourself.