What's the best investing strategy with borrowed equity and no active work?

[Johann Jells]

Here's the story, we do buy and hold, but I've got more fixer-uppers than I can handle right now, so I don't want another.  But rates won't stay this low. One of my properties is paid off and has appreciated ridiculously, so I'm sitting on a ton of equity. It seems like a smart idea to borrow that out and do something with it. The usual way would be to borrow the downpayment and buy a property with neutral or better cashflow. But like I said, I'm over my head in maintenance as it is. 

So how can I put this equity to work? A moron might borrow and invest in stocks.  One possibility  is to buy one of the high value condos around here. Same price as our multis, but new instead of a century old and a fraction the sinks, toilets, heating systems etc.  I'm just not sure they wouldn't be negative.  A foreclosure and gut rehab would require that kind of financial muscle, but I don't want to get into that, good contractors are impossible to find. Arbitraging the difference between our rate and hard money rates seems a bad plan. Any great ideas out there?