Thanks Hood. The linear blocks are attached to the carriage for a few reasons. First flipping them around would have meant I had to drill 24 through holes in the cross slide right where the T-slots are, which preferred not to. Second, I did the design before I thought of putting a sheet metal guard on top to keep chips away and when the rails are on the top part they will always stay clean. With a guard it won't mean much, but it was a consideration at the beginning. And lastly I wanted to gain more X travel. The carriage is shorter then the cross slide and I couldn't mount the same length rails on the carriage.
I know that it may be problematic and I also had Graham tell me that I may have overhang problems this way. When the blocks are on the moving part the load on them is always the same regardless of their position. In my configuration the blocks are stationary, meaning the load on them will vary with the cross slide position. It's same as on a mill, where gaining X travel is desired and then you have a long table riding on a short bed. But the little difference is that on a mill the load is always at the bed centre
Anyway, I can always limit the stroke if I see chatter problems at the extents. And if it's really bad I will consider flipping them over.