I tried converting the system using a pre-allocated disk. This time, the numbers look right:
2013-09-08T23:40:25.671-04:00 [04948 info 'Default'] Disk signature found 1101734678, disk size in sectors 293121990, sector size 512
2013-09-08T23:40:25.671-04:00 [04948 info 'Default'] Partition found type Unknown(222) name:Unknown start:63 size:112392 primary
2013-09-08T23:40:25.671-04:00 [04948 info 'Default'] Partition found type HPFS/NTFS(7) name:HPFS/NTFS start:112455 size:292977405 active primary
2013-09-08T23:40:25.671-04:00 [04948 info 'Default'] Disk with signature 1101734678, recognized partitions 2
I haven't looked at the data yet (I will), but I imagine it's fine.
So... this leads me to believe that the problem may be the fact that this is an XP system that I added a second physical disk to, and installed Win 7 on it. When I boot, it goes to the Win 7 boot screen with "Older Windows Installation" and "Windows 7", which presumably means the boot sector points to this bootloader, not the boot.ini on the XP disk, much as described in:
"This issue occurs when converting a physical machine that uses Boot Configuration Data or BCD (Windows Vista, 7, Windows Server 2008, Windows Server 2008 R2). In this case, the physical machine may have some type of system, hidden, or recovery partition that results in inaccurate BCD configuration data after the conversion and causes the virtual machine reconfiguration process to fail."
Going to see if I can find my Dell XP install CD... and do what it says there.