A while back there was a guy here who was trying to design a plumber's creeper while the idea is intriguing. with the already severely limited space the application would prove detrimental in most cases.
Access to working areas under the kitchen sink or the lavatory in a bathroom are almost always further reduced by the poorly designed plumbing fixtures we find as American standard even high end fixtures are little more than fancy versions of the cheaper varieties Traps and drain locations, (IMO) have never been well designed
When I was working un my kitchen I wanted to incorporate a more European trap 7 drain system but to do so would have meant tearing out the entire back wall, ripping up a section of the floor and rerouting just about everything. Not an expense or time element I was willing to commit for just so I could have a cleaner under sink cavity.and even that would not have been without its problems later in life since almost everything now days is made of plastic