I just got off the phone with a Domo rep. Turns out that Sage is a Domo Partner, AND an investor!
The rep was pretty good about answering my questions about cost, etc. Typically this is $50k/yr, and there is usually implementation at first. However, the implementation is more along the lines of applied training, as customers generally make the changes needed over time themselves. Domo creates all the connectors themselves; there is no SDK-equivalent.