sysctl -a is not on the Netgear WNDR3700 V4 (r42813)
but is on the EA8500 (r46380) & (r44786)
WNDR3700v4 (r42813) = 24.4 MB (24,403,996 bytes)
EA8500 (r46380) = 23.8 MB (23,789,568 bytes)
EA8500 (r44786) = 22.8 MB (22,847,488 bytes)
Opening tickets about devices not having certain features that may have been left out due to flash space restrictions is sometimes pointless. I can email BrainSlayer about it, but I cannot promise that it will be fixed.
The WNDR4500 has ample flash. 128MB of it while the Giga build is only around 24MB so far. Since makers seem to like to use even multiples for flash I would guess there's devices with 16MB flash chips that are too small for Giga, and devices with 32MB of flash that are plenty large for Giga, but I suspect there's no devices with 24MB flash and that Giga just barely fits into where saving a few K for omitting the sysctl program is significant.
I seem to recall reading about devices with large flash space still only being able to have firmware images that were only a certain size.
Yes, I have 3 of those devices. The EA6300 and it's friends are like that - Linksys split the flash into 2 partitions and halved the size of the nvram from 64k to 32k. The ASUS N16 is another. All very brain-dead devices since they have plenty of CPU and flash but due to the nvram issue are almost worthless to use as anything other than access points. Someone figured out a hack for the ASUS devices and there's instructions to fix the CFE for several of the EAs buried in the archives. None are Giga candidates, though.