I'm not sure Rick Steves ever will (though I'd love it if he did!). I think a big part of what makes Rick Steves' Europe so valuable and worthwhile when it comes to European travel is his decades of experience traveling to Europe, his extensive knowledge of European history and culture, his network of guides there, and the many months per year he continues to spend there. It could be difficult to come up with similar offerings on South America, without similar years of extensive work and experience going in to it.
South America (and even Central) do have quite a lot to offer, though.
Costa Rica is a safe and stable country, hugely popular with tourists for it's amazing nature and adventure travel options - gorgeous beaches and jungles, a well-established tourism infrastructure, English commonly spoken.
In South America, I'd second the Ecuador suggestion. I was lucky enough to have lived there for 5 years as a teenager and you'd be hardpressed to find a country that can offer so much, within such a small footprint. It has some of the Andes' most impressive mountains and volcanoes, pristine Amazonian rainforest to their east and cloudforests to their west, amazing beaches, the Galapagos, well-preserved Spanish colonial architecture, indigenous culture, and even great climate.
If you want to visit South America but get a taste of Europe in it, Argentina and Uruguay could be worth looking at. Argentina in particular might seem reasonably familiar to people who have traveled to Europe. Buenos Aires gets called the Paris of South America (ok... perhaps a bit of a stretch). BsAs is a lively, sophisticated city, the food is amazing (assuming you like red meat and lots of it), Patagonia is stunningly beautiful (and has cities and towns that look like they were pulled out of the Alps or southern Germany and dropped in to Argentina). There's opera and flamenco, and you might never run out of wineries to visit if that's your thing.
I really could go on and on and write paragraphs encouraging people to visit Colombia, Bolivia, Peru, and Chile as well (Beyond living in Ecuador before, I took a year off from college and ventured down to La Paz, Bolivia, and used that as a home base to backpack through South America, with multiple visits to various parts of South America since). Indeed, I'd even say it's the ideal continent for someone who has visited Europe before and wants to try out something new, with hints of things they'd find familiar from European travels (some of the languages, architecture, religious elements, cuisine). It can be quite affordable, also - a welcome break from some of Western Europe's pricier destinations, just as parts of eastern/southeastern Europe might be.
But really it comes down to what you're after? Nature? History? Cities? Food and Wine? What you're after will help determine where you'll go, and you'll be amazed at how much of what you want can be found in a single country.
As tyrker mentioned, Footprint guides are pretty much the best you can get for South America (not just South America as a whole with their Handbook, but also individual countries). They're also the best about keeping their books updated. Having said that, I relied on Lonely Planet guides in years past and loved those. The books they do have are great, though their South America offerings aren't as extensive as Footprint's. They tend to be quite backpacker focused, but still very useful for all.