If utility is more important that looks, a stem riser will get you a long way (well 50 - 80 mm, about 2 to 3 inches). There are various makers, but they all look more or less like this one. Prices run from about US $15 to $30. The riser and the existing spacers take care of the holding the headset, you don't need spacers under the stem with the riser – just the spacers between the bottom of the riser and the headset.
After that an adjustable stem like you suggested and/or bars with an upward bend will all help. Shortening the reach may also help.
Keep in mind that as you raise the bars you may find that cables are coming up short. You may have already done this, but a "trick" that works for me is to "visualize" where I want the bars by riding with my fingertips or even no-hands as I look for a place where I will feel comfortable. I've found that I can get very close this way and it's a lot less work (and money) than changing parts. Once I know about where I want the bars, I buy the parts to fit.