No Studio UI to switch boards yet, so make a dummy board that is used by all projects, and have a Select-By-Config module select the actual board drivers.

LUFA/StudioIntegration/lufa_common.xml

@@ -29,6 +29,13 @@
 			<build type="header-file" value="Common/BoardTypes.h"/>
 			<build type="header-file" value="Common/CompilerSpecific.h"/>
 			<build type="header-file" value="Common/Endianness.h"/>
+
+			<require idref="lufa.common.dummyboard"/>
+			<require idref="lufa.drivers.board"/>
 		</module>
+
+		<board id="lufa.common.dummyboard" vendor="LUFA" caption="NONE">
+			<device-support value="avr"/>
+		</board>
 	</asf>
 </lufa>

LUFA/StudioIntegration/lufa_drivers_board.xml

@@ -75,5 +75,48 @@
 			<build type="include-path" value=".."/>
 			<build type="header-file"  subtype="api" value="Drivers/Board/Temperature.h"/>
 		</module>
+
+		<select-by-config id="lufa.drivers.board" name="lufa.drivers.board.name" default="none" caption="LUFA Board Support">
+			<module id="lufa.drivers.board#none" name="None">
+				<device-support value="avr"/>
+
+				<build type="define" name="BOARD" value="BOARD_NONE"/>
+			</module>
+
+			<module id="lufa.drivers.board#usbkey" name="USBKEY">
+				<device-support value="at90usb1287"/>
+
+				<require idref="lufa.drivers.misc.at45db642d"/>
+
+				<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Buttons.h"/>
+				<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Dataflash.h"/>
+				<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Joystick.h"/>
+				<build type="header-file" value="Drivers/Board/AVR8/USBKEY/LEDs.h"/>
+
+				<build type="define" name="BOARD" value="BOARD_USBKEY"/>
+			</module>
+
+			<module id="lufa.drivers.board#xplain_rev1" name="XPLAIN (HW Rev 1)">
+				<device-support value="at90usb1287"/>
+
+				<require idref="lufa.drivers.misc.at45db642d"/>
+
+				<build type="header-file" value="Drivers/Board/AVR8/XPLAIN/Dataflash.h"/>
+				<build type="header-file" value="Drivers/Board/AVR8/XPLAIN/LEDs.h"/>
+
+				<build type="define" name="BOARD" value="BOARD_XPLAIN_REV1"/>
+			</module>
+
+			<module id="lufa.drivers.board#xplain" name="XPLAIN (HW Rev 2+)">
+				<device-support value="at90usb1287"/>
+
+				<require idref="lufa.drivers.misc.at45db642d"/>
+
+				<build type="header-file" value="Drivers/Board/AVR8/XPLAIN/Dataflash.h"/>
+				<build type="header-file" value="Drivers/Board/AVR8/XPLAIN/LEDs.h"/>
+
+				<build type="define" name="BOARD" value="BOARD_XPLAIN"/>
+			</module>
+		</select-by-config>
 	</asf>
 </lufa>

LUFA/StudioIntegration/lufa_drivers_board_avr8_usbkey.xml

@@ -1,26 +0,0 @@
-<!--
-             LUFA Library
-     Copyright (C) Dean Camera, 2013.
-
-  dean [at] fourwalledcubicle [dot] com
-           www.lufa-lib.org
--->
-
-<!-- Atmel Studio framework integration file -->
-
-<lufa>
-	<asf>
-		<board id="lufa.drivers.board.usbkey" vendor="Atmel" caption="USBKEY">
-			<device-support value="at90usb1287"/>
-
-			<require idref="lufa.drivers.misc.at45db642d"/>
-
-			<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Buttons.h"/>
-			<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Dataflash.h"/>
-			<build type="header-file" value="Drivers/Board/AVR8/USBKEY/Joystick.h"/>
-			<build type="header-file" value="Drivers/Board/AVR8/USBKEY/LEDs.h"/>
-
-			<build type="define" name="BOARD" value="BOARD_USBKEY"/>
-		</board>
-	</asf>
-</lufa>

LUFA/StudioIntegration/lufa_drivers_board_none.xml

@@ -1,18 +0,0 @@
-<!--
-             LUFA Library
-     Copyright (C) Dean Camera, 2013.
-
-  dean [at] fourwalledcubicle [dot] com
-           www.lufa-lib.org
--->
-
-<!-- Atmel Studio framework integration file -->
-
-<lufa>
-	<asf>
-		<board id="lufa.drivers.board.none" vendor="N/A" caption="NONE">
-			<device-support value="avr"/>
-			<build type="define" name="BOARD" value="BOARD_NONE"/>
-		</board>
-	</asf>
-</lufa>