Hi Tony,
We can't recommend any homemade sidemount rigs, the intricacies in design that keep the diver safe, in good trim and comfortable in the water is what's available in the commercial rigs on the market now. It's not so much about putting the various pieces together, but how the sewing/transition points and other features work as a whole to give you the support you need in the water.
I know sidemount rigs are expensive and there are some divers who prefer to make their own for cost reasons, however for both safety and enjoyment I always advise a commercial rig. Sidemount is a different animal and even slight variances can throw off your trim or remove redundancies necessary in an emergency. We've seen this so often, again I would urge you to consider a sidemount specific rig.
Sorry if this isn't what you'd hope to hear,
Kathleen