Dell desktop / laptop with UEFI

Understand that Microsoft require Windows 8 to enable secure boot in UEFI and typically for 64bit version OS. Can I purchase a Dell machine with UEFI now to be used with Win7 /32 or 64 bit and use the same machine for future upgrade to Win8 32/64bit.

Understand that UEFI is only supported for 64 bit architecture but ARM processor is currently in 32-bit therefore I am kinda confuse whether 32-bit OS will support UEFI?