the problem of managing appliations 64bit does not arise, it is only the start mode is 32 bit, the 32 and 64 bit applications work fine on ML10.8 DP1, somehow the kernel behaves like the Lion 10.7. the core is capable i386 and x86_64.
it's a shame that it is not continued on the following versions of the kernel. This is purely commercial, because I think Apple wanted to eliminate firmwire 32 bit Macs.
for DP1, it is easy to start, just write the ref model efi32 in System / coreservice / PlatformSupport.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>SupportedBoardIds</key>
<array>
<string>Mac-F42D88C8</string>
<string>Mac-F2218EA9</string>
<string>Mac-F42D86A9</string>
<string>Mac-F22C8AC8</string>
<string>Mac-942B59F58194171B</string>
<string>Mac-F226BEC8</string>
<string>Mac-F2268DC8</string>
<string>Mac-7BA5B2794B2CDB12</string>
<string>Mac-F22C89C8</string>
<string>Mac-942459F5819B171B</string>
<string>Mac-F42388C8</string>
<string>Mac-F223BEC8</string>
<string>Mac-F4238CC8</string>
<string>Mac-F222BEC8</string>
<string>Mac-F227BEC8</string>
<string>Mac-F2208EC8</string>
<string>Mac-F4238BC8</string>
<string>Mac-F221BEC8</string>
<string>Mac-C08A6BB70A942AC2</string>
<string>Mac-8ED6AF5B48C039E1</string>
<string>Mac-F2238AC8</string>
<string>Mac-F22586C8</string>
<string>Mac-F2268EC8</string>
<string>Mac-F22589C8</string>
<string>Mac-F22587A1</string>
<string>Mac-F22788AA</string>
<string>Mac-F42C86C8</string>
<string>Mac-942C5DF58193131B</string>
<string>Mac-F2238BAE</string>
<string>Mac-F22C86C8</string>
<string>Mac-F2268CC8</string>
<string>Mac-F2218FC8</string>
<string>Mac-742912EFDBEE19B3</string>
<string>Mac-F42D89C8</string>
<string>Mac-F22587C8</string>
<string>Mac-F42D89A9</string>
<string>Mac-F2268AC8</string>
<string>Mac-F42C89C8</string>
<string>Mac-942452F5819B1C1B</string>
<string>Mac-F2218FA9</string>
<string>Mac-F221DCC8</string>
<string>Mac-94245B3640C91C81</string>
<string>Mac-F42D86C8</string>
<string>Mac-4BC72D62AD45599E</string>
<string>Mac-F2268DAE</string>
<string>Mac-F42C88C8</string>
<string>Mac-94245A3940C91C80</string>
<string>Mac-F42386C8</string>
<string>Mac-942B5BF58194151B</string>
<string>Mac-F2218EC8</string>
</array>
<key>SupportedModelProperties</key>
<array>
<string>MacBookPro4,1</string>
<string>Macmini5,3</string>
<string>Macmini5,2</string>
<string>Macmini5,1</string>
<string>MacBookPro5,1</string>
<string>MacPro4,1</string>
<string>MacBookPro5,2</string>
<string>iMac8,1</string>
<string>MacBookAir4,2</string>
<string>iMac11,1</string>
<string>iMac11,2</string>
<string>iMac11,3</string>
<string>MacBookPro8,2</string>
<string>MacBookPro3,1</string>
<string>MacPro5,1</string>
<string>iMac9,1</string>
<string>Macmini3,1</string>
<string>MacBookPro6,1</string>
<string>iMac12,2</string>
<string>iMac12,1</string>
<string>MacBook5,1</string>
<string>MacBook5,2</string>
<string>iMac10,1</string>
<string>MacBookPro7,1</string>
<string>MacBookAir4,1</string>
<string>XServe3,1</string>
<string>MacBookPro5,3</string>
<string>MacBookPro6,2</string>
<string>MacBookPro5,5</string>
<string>MacBookAir3,1</string>
<string>MacBookAir3,2</string>
<string>Macmini4,1</string>
<string>MacBookAir2,1</string>
<string>MacBookPro8,1</string>
<string>MacBook7,1</string>
<string>MacBookPro8,3</string>
<string>iMac7,1</string>
<string>MacBook6,1</string>
<string>MacPro3,1</string>
</array>
</dict>
</plist>