There are about 5 general options to lift a factory type leaf spring suspension.
1) Extended shackles; this is a cheap option if the shackles are of the compression type.
^ This is an example of a compression type shackle
^ This is an example of a shackle in tension, in which case, extending the shackles lowers
your truck. This type of shackle would first require a shackle-flip, which by itself would add a few inches of suspension lift.
There is a limit to how much you can safely lift a truck using longer shackles. Personally I wouldn't go more than 2 inch longer shackles due to stability issues. As you also mentioned, you gain only half the amount of lift from shackles. However you could gain some lift with shackles if you also drop the front spring hanger
2) Lift springs; Many suspension lift kits typically include new leaf springs which increase ride height by incorporating a greater amount of spring arch. However, depending on the manufacturer of the springs, they are not all the same. Some springs may tend to be stiffer while some are called soft ride springs. When buying springs I would tend towards the soft ride springs for greater articulation.
3) When new lift springs aren't available, an older set of springs can be re-arched. This can be performed by spring shops which specialize in leaf springs. The downside is, there are not that many spring shops.
4) Lift blocks. This is an old school method of lifting and it can be relatively cheap, but this can also be dangerous if pushed to the extremes and could cause damage to the suspension, in the form of axle wrap. First thing however is never use blocks on a front leaf spring suspension. Besides being illegal in many states, their use on front suspensions is very dangerous because the leverage they can create can cause the axle to twist, changing your critical caster angle and making it impossible to steer when panic or hard braking. Also blocks in front are known to pop out. This isn't exactly a problem for your average Dakota or Durango since they all use an IFS suspension system, but if you have plans for a solid axle swap and plan to use leaf springs, heed this warning. For the rear suspension, blocks are fine, so long as they aren't too tall. But keep in mind that axle wrap will increase with taller blocks which may require adding some kind of traction device to control wrap.
5) Add-a-Leafs; Basically an add-a-leaf is a single highly arched leaf spring which you place into an existing leaf spring pack. When tightened, it forces the rest of the springs in the pack to conform to the arch which lifts the truck. The main problem with add-a-leafs is they greatly increase ride harshness. However, as I understand it, there are soft ride AALs on the market, but I can't say for certain if they ride as well as advertised.
Each method of lift comes with pros and cons, but you can also combine some of these methods to minimize the cons. However if none of these options will work for your needs, the next option is to go custom suspension and that can involve 4 link w/ coils (or coil-overs) or older school quarter elliptic rear suspension, etc.