The Minolta corded ones pop up a lot. They will work on the Sony's as well, as is what I use for corded. It has a locking feature that will keep it open. For interval stuff there are a few Chinese ones that are basically knockoffs of the Nikon or Canon ones. I forget which model mine is. I'll try and find it.
Mine looks like this one:
Opteka Timer Intervalometer Time Lapse Remote Control for Sony Alpha A A33 A55 | eBay
Those Phottix flash triggers double as a remote shutter, but it will only fire your camera for whatever shutter speed you have set.