I've made headway on the wheel brackets, the most complicated piece of joinery so far. Shaping was by drill press, rasp, router and sand paper. The pieces are attached using 3 small 10x10mm mortises with wedges. Glued with titebond 3 provide a very strong joint. Tenons were cut using a small dozuki hand saw.
By why do I need a wheel bracket? When Jameel at Khalaf Oud Luthiery (who developed the bench crafted vices) first made his roubo he used rollar blade wheels to reduce friction on the parallel guide.
The bench crafted design (see above) using two bolts in line with the parallel vice to allow fine tuning. As I wanted the entire mechanism below the shelf I moved the bolts to the side. The pro's and con's (namely justed inline strength and complexity of build) of this have been discussed. I have to fill a few small gaps with epoxy, a little bit of sanding, and the brackets are ready to roll. (Pun intended.)