BoM.txt

Qty	Component
17	Cherry MX switches (or clones)
17	SMD Diode - SOD123 package | Digikey # 497-7546-1-ND
2	SMD 22Ω resistor - 0805 package | Digikey # P22ACT-ND
2	SMD 10kΩ resistor - 0805 package | Digikey # P10KACT-ND
2	SMD 1µF capacitor - 0805 package | Digikey # 1276-1246-1-ND
2	SMD 20pF capacitor - 0805 package | Digikey # 1276-1829-1-ND
1	16 MHz crystal | Digikey # 631-1108-ND
1	Connector Receptacle mini B USB | Digikey # WM17115-ND
1	SWITCH TACTILE SPST | Digikey # 679-2428-ND
1	ATmega32U2-AU | Digikey # ATMEGA32U2-AU-ND

All components but the switches must be soldered at the bottom side, even the through hole components.

Links to quick add all components on Digi-Key cart, by Cherry MX switch type:

MX black: http://www.digikey.com/short/3hwrn9
MX blue:  http://www.digikey.com/short/3hwrnn
MX clear: http://www.digikey.com/short/3hwrd8

If your desired switch isn't in the list, just delete the ones included on the cart before checking out.