I think you might want to re-think your premise - a shallower section rim will not necessarily provide a more compliant ride. There are two reasons - the first is academic, and the second is practical:
1) Wheel vertical stiffness is governed more by the spokes than by the rim. A wheel with a deep, heavy rim and a small number of spokes will actually be more compliant than a wheel with a shallow rim and a large number of spokes. If you think about this, it makes sense -vertical compliance is when the hub gets closer to the ground, and since the spokes are in a direct line between the hub and the ground, the number and thickness of the spokes will determine how much force it takes for the hub to move a given distance relative to the ground (i.e., the vertical stiffness of the wheel). This principle is not just theory, it has been directly measured many times. Here's a good source about when Zipp was designing wheels for the Paris-Roubaix, and found out that carbon rim wheels were actually more compliant than the wheels with shallow aluminum box section rims that were previously favored:https://silca.cc/blogs/journal/115178628-road-to-roubaix-the-complete-story
Here's another test showing measured wheel stiffnesses. Note that the stiffest wheel in the test had lightest, shallowest rim (GEL330) - but it also had the most and thickest spokes (36 2.0mm straight gauge):https://www.sheldonbrown.com/rinard/wheel/grignon.htm
2) And now the practical (and real) answer: As you can see from the wheel stiffness tests above, all wheels have very, very high vertical stiffness. So high, that they provide no meaningful compliance/comfort. Here's an article which includes a discussion of riders doing blinded tests on wheels, and it was found that riders couldn't really feel any stiffness differences between them:http://www.slowtwitch.com/Tech/Thoughts_on_science_perception_4571.html
Cervelo measured the compliance of the various components between the road and the rider, and found that wheels had the least compliance of all the components. While it should not be surprising that the tires had the most compliance, they found that even the handlebar tape had several times more affect on compliance than the front wheel. Or in other words, even choosing the most compliant wheels will have less affect on the ride than selection of handlebar tape or shorts.http://weightweenies.starbike.com/forum/posting.php?f=113&mode=reply&t=147395
So therefore, you're selection of rims should be based on other factors (strength, durability, weight, aerodynamics, etc.), and not at all on ride compliance.