Are there actually merchant services for "outgoing" processing?
I was the OP of that last question that you referenced. 

Tracking the 'receives' is actually very easy. There are plenty of free APIs (e.g.  BlockExplorer, BitPay/Insight) that'll let you check the status of your inbound BTC transactions with a single API call. It's really a no-brainer.

Sends, on the other hand, are harder to deal with. As opposed to a receive, whose status can be polled with a couple lines of code, a send requires signing using private keys and for obvious reasons, you don't want to broadcast your private keys through a public API. This is what led me down the path of building my own transactions programmatically.

Since the time I wrote that code, quite a few APIs have been made available. BlockCypher, for example, can assist you in building a binary transaction without requiring you to expose your private keys. Building binary transactions isn't exactly straight-forward though, even with an API. Could a person use one of these APIs to build a transaction without having some knowledge of crypto and the native transaction format? Yeah, perhaps, but still not a particularly pleasant process.

Remember, if all you're trying to do is accept Bitcoins for an online store or as payment for services rendered, there's absolutely no need to mess around with any of that low-level stuff that I referenced in my question. Just use a third party service like BitPay. They'll handle all the grunt work including invoicing, transaction building for customer refunds, etc. When I pay for my servers, domains, certs, etc. with BTC I don't think I've ever seen a vendor roll their own Bitcoin billing interface. It always goes through BitPay or a similar service.

My needs and business model are so unusual and specific that a standard package like Bitpay wouldn't work for me. For most use cases though, standard merchant services are the way to go.