Any plans to support Elavon's Converge payment gateway?
Nope, we do not implement any additional gateways unless the demand is high enough for it. Gateways are costly to implement. Taking significant development time and upkeep. See the Stripe post below for a successful campaign to have a new gateway implemented.
www.joomlapolis.com/forum/87-presales/223436-stripe?limitstart=0
Your alternative would be to try and find an experienced Joomla and CB developer to develop it for you.
What is it that this gateway specifically provides that you need? I recommend taking a look at Stripe where we support all of Stripes various payment methods.