Yes, there is a T99 carbine based on the T99 rifle. Over the years there have been a lot of comments about the carbine configuration, so thought I'd post a few detail photos of the example I have. And, no, I do not believe there was ever a serious effort to produce a 7.7 carbine in quantity. I would bet that production was made to conserve critical materials or make maximum use of reject barrels. The bottom photo on page 114 of the 5th edition of MROJ (maybe some earlier editions also) shows a Kasuga factory of Kokura Arsenal T99 carbine with a 19 in barrel. One of the keys to this being a correct carbine is the varient front sight. It is similar to but not identical to the T44 carbine front sight and features both Kokura 2nd factory and Kasuga inspection symbols (see page 13 of MROJ). Ears were machined off the sight to facilitate installation of the front band. The sight fits properly, and blue matches the rest of the rifle. This is a very rare rifle, a proud addition to my collection. I've not seen another but do believe they're out there.