Depends on the environment that the structure is in. Uplift, seismic, do you need it to be a moment connection, what kind of bracing is in the structure, etc. etc.

If you need a moment connection to keep things rigid, the simple epoxy rod / stand off might not work.

Simpson makes a bunch of off the shelf options - most of them aren't pretty:
http://www.strongtie.com/products/categories/caps-bases.html

You can do this yourself and order plastic for the base part from McMaster-Carr or similar. You can also use a plate of stainless. The rod should be off the shelf at a local supply house. Depending on where you are, stainless rod / connections might be worth the extra $$.

But again, it really depends on the specifics.