There is long and somewhat complex story behind the it. First, the Chinese DAP maker 'Cube' makes the C30 for the Chinese market, HiSound then contracted Cube to co-develop a 'hi-fi' version of the small player called the Rocoo using HiSound. The housing is the same (with different color), the hardware idea comes mainly from HiSound, but Cube is responsible for manufacturing (= partially OEM). The agreement is, Cube will sell C30 in China while HiSound will sell the Rocoo oversea, but later on HiSound breached the contract (by selling Rocoo in China) and pissed off Cube (they actually started quite a few flamewar in various Chinese forums). In the end, HiSound agreed to follow the original contract and stop selling Rocoo in China - at least that is what I know. The Gumstick, as far as my understanding goes, is contracted to HiSound by Hippo and it is actually a modified version of Rocoo's (one of) original design by adapting a SigmaTel chip (same as C30) but use a Class-A biased output like the Rocoo, so you can say it is a half-blood b/w a Rocco and a C30. Cube, presumably is likely to be responsible for manufacturing as well, of course I can't really confirm that. Firmware wise, I think they all works on their own.
Edited by ClieOS - 9/27/10 at 1:09am