The Simplicity Elizabethan corset pattern, 2621, has a pretty high back, but the straps are super-long (and crazy narrow), so you'll want to check the fit before binding them.
Otherwise, if you're mostly happy with the fit of your current pattern, the back neckline is *easy* to change! This looks like a good basic tutorial (it's for a shirt or mundane dress, but the principles are the same): http://www.sugartartcrafts.com/2013/06/how-to-change-shape-of-neckline-and.html
This is one of the alterations I do on pretty much everything I make for myself, and because of the related fit issues, my bodice patterns almost all have a center back seam (instead of being cut on the fold), which really allows me to fine-tune the fit so it follows the curve of my spine and fits me snugly up to wherever I decide I want the neckline to fall.
Start by tracing your pattern onto muslin, and draw the neckline like a jewel-neck T shirt: just the teeniest curve right at the base of your neck. This will allow you to assess the fit and decide where the straps should go to have the maximum chance of staying on your shoulders. But it's fair to note that, some of us just have Strap Issues. My shoulders are so narrow they are literally off the sizing charts, and it's almost impossible for me to keep my straps up--particularly if I have tie-on sleeves. A few things will *help,* although none of it is fool-proof: 1.) Never, ever hang your bodices or dresses on hangers by the straps. That will guarantee that your straps, if they weren't too long to start, end up too long!
2.) Make your back necklines high and narrow, like this
instead of this
. The closer they start to the base of your neck, the less room they have to slip. 3.) Make your armscyes high and snug; this will increase your range of motion for your arm and again *decrease* the range of motion for the strap.
4.) Cut your straps on the bias of the fabric, instead of straight, so they have some natural stretch to them. It makes it easier to fit them snugly. 4.) Make your straps nice and wide. This isn't terribly period, but these straps
don't generally slip on me. (shrug)
...For the coral colored dress with the yellow sleeves, I ended up taking a crescent-shaped piece of fabric and filling in the back neckline by about 3". It helps significantly, but even so, by the end of the day I am tugging those silly things back in place.