I have used Hemlock.

It has a reputation as prone to shake and rot.

This does not necessarily mean that it is completely unsuitable to framing, only that it should be carefully examined during the sawing and timber framing stages. Ring shake can be pretty scary, and completely compromise the structural properties of a timber.

Normally, hiring a consulting forester for advice in these matters is the most efficient way to proceed. For instance, it may be that there is a local market for Hemlock in your area that would generate enough cash for you to buy another species of framing timber that might be better suited to your project.