Those Japanese saws that people are linking - those are all pole saws for trimming brnaches, not carpenter's saws. While they will work for cross-cutting, they would be poor for ripping tenon cheeks as they have cross-cut teeth only.

A more suitable choice for the size of material you wish to work would be a 300~330mm ryoba (double-sided saw). Unfortunately, the selection of that size of saw available in the US is rather limited. Of the people here who go in for Japanese tools, the largest contingent tend to be furniture makers and not timber framers, so the products brought in serves that group more than any other. That's why all you tend to see are the 180~240mm size saws. I can assure you that Japanese saws are available, in Japan, in a vast array of sizes and types.

Hida Tool in Berkeley sells a machine-made 300mm ryoba by Gyokucho (model D-GC-#616) that would be adequate, and is just under $40. If you want a 330mm saw from them, all they list is a medium-quality Mitsukawa ("log saw") which is selling at $360 or so, likely too steep for most folks.

~Chris