Well, if people were willing to take the risk, I'd be happy to make them available in that way as well. However, I don't want to promote a false sense of security when there is a risk factor that needs to be considered.
Now, I've done what I can engineering-wise to minimize that risk factor. The tubing is thick-walled and seamless. The billet connector piece is done in such a way that the stress is not applied directly onto the brazed-joint. (In fact, I designed the connector piece to just be an upsized version of what the clever Stromberg guys use on their carb setups). Lastly, I use a high-silver content braze alloy (%56 silver) which adds a little flexibility compared to cheaper, lower-silver content, brazing alloys. A welded joint would be much worse. Still, all of that being considered, that is a LONG stretch of unsupported and ridged metal. All it takes is one failure for someone to have a very bad day.
In regards to phenolic spacers, I generally agree. When most people are referring to them, they are referring to the spacers that are plastic with O-rings. With those poorly designed parts, it's not a matter of if, but when, they will leak. However, a spacer cut entirely from a suitable material (like Kevlar), would be helpful to those looking to reduce vibration-related maladies. Being made from a "soft" monogenous material means that the entire face would be used to seal/dampen, as opposed to just the o-ring.